CVE-2026-93575 (GCVE-0-2026-93575)
Vulnerability from cvelistv5 – Published: 2026-09-18 10:53 – Updated: 2026-09-18 13:32
VLAI
EPSS
VEX
Title
Io.netty/netty-codec-mqtt: netty: resource exhaustion in mqttdecoder
Summary
### Summary
Netty's fix for CVE-2026-44248 is incomplete. The decoder checks if the MQTT packet's `Remaining Length` exceeds `maxBytesInMessage`, but fails to validate the `Properties Length` against the `Remaining Length`. An attacker can bypass the size limit by sending a small `Remaining Length` but an enormous `Properties Length`. This forces Netty to buffer and parse millions of properties, allowing an unauthenticated remote attacker to trigger excessive memory and CPU consumption, leading to OutOfMemoryError.
### Details
In `io.netty.handler.codec.mqtt.MqttDecoder`, the `decodeProperties()` helper method reads `totalPropertiesLength` and attempts to parse that many bytes. If the buffer lacks the full length, a `Signal` is thrown. The `catch` block inside `decode()` only enforces `maxBytesInMessage` against `bytesRemainingBeforeVariableHeader` (the packet's `Remaining Length`).
By sending a `CONNECT` packet with a small `Remaining Length` but a huge `Properties Length`, the size check passes. `ReplayingDecoder` then buffers data from the network until the huge `Properties Length` is reached, parsing millions of `UserProperty` objects and exhausting CPU and memory.
#
Severity
7.5 (High)
CWE
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-93575 | vdb-entryx_refsource_REDHAT |
| https://bugzilla.redhat.com/show_bug.cgi?id=2536967 | issue-trackingx_refsource_REDHAT |
Impacted products
5 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Red Hat | Red Hat AMQ Broker 7 |
cpe:/a:redhat:amq_broker:7
|
||
| Red Hat | Red Hat build of Apache Camel for Spring Boot 4 |
cpe:/a:redhat:camel_spring_boot:4
|
||
| 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 Single Sign-On 7 |
cpe:/a:redhat:red_hat_single_sign_on:7
|
Date Public
2026-09-10 00:53
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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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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