CWE-205
AllowedObservable Behavioral Discrepancy
Abstraction: Base · Status: Incomplete
The product's behaviors indicate important differences that may be observed by unauthorized actors in a way that reveals (1) its internal state or decision process, or (2) differences from other products with equivalent functionality.
6 vulnerabilities reference this CWE, most recent first.
CVE-2026-109125 (GCVE-0-2026-109125)
Vulnerability from cvelistv5 – Published: 2026-10-21 08:56 – Updated: 2026-10-21 08:56- CWE-205 - Observable Behavioral Discrepancy
| URL | Tags |
|---|---|
| https://www.nlnetlabs.nl/downloads/unbound/CVE-20… | vendor-advisory |
| Vendor | Product | Version | |
|---|---|---|---|
| NLnet Labs | Unbound |
Affected:
0 , < 1.26.2
(semver)
|
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Unbound",
"vendor": "NLnet Labs",
"versions": [
{
"lessThan": "1.26.2",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "TaoFei Guo (Peking University)"
},
{
"lang": "en",
"type": "finder",
"value": "Yang Luo (Tsinghua University)"
},
{
"lang": "en",
"type": "finder",
"value": "JianJun Chen (Tsinghua University)"
}
],
"datePublic": "2026-10-21T00:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "In NLnet Labs Unbound up to and including version 1.26.1, an observable cache-level side-channel can be exposed with \u0027unwanted-reply-threshold \u003e 0\u0027 configurations (not a default configuration). If a response-like UDP datagram reaches the upstream source port currently used by a recursive query, but its TXID does not match any pending query, Unbound counts the packet as an unwanted reply. When the accumulated count reaches the configured threshold, Unbound clears the worker\u0027s RRset cache and message cache. This cache clear action does not destroy the current upstream UDP pending query. Therefore, an external observer can distinguish whether a candidate port matches the current upstream source port by checking whether an existing cached item has been cleared. This is a cache side-channel vulnerability that can be used to probe the upstream source port. Although the attack is not feasible on default configurations and the suggested value (10 million) makes it an ureliable attack on a public resolver, in scenarios where the attacker can keep a concurrent query window alive, the attacker can first filter the source port and then perform birthday-style guessing against the TXID, making cache poisoning a feasible attack path."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-205",
"description": "CWE-205: Observable Behavioral Discrepancy",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-21T08:56:35.696Z",
"orgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
"shortName": "NLnet Labs"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-109125.txt"
}
],
"solutions": [
{
"lang": "en",
"value": "This issue is fixed starting with version 1.26.2"
}
],
"timeline": [
{
"lang": "en",
"time": "2026-09-28T00:00:00.000Z",
"value": "Issue reported by TaoFei Guo"
},
{
"lang": "en",
"time": "2026-10-05T00:00:00.000Z",
"value": "NLnet Labs shares patch"
},
{
"lang": "en",
"time": "2026-10-06T00:00:00.000Z",
"value": "TaoFei Guo verifies patch"
},
{
"lang": "en",
"time": "2026-10-21T00:00:00.000Z",
"value": "Fixes released with version 1.26.2"
}
],
"title": "Possible cache poisoning vulnerability via a cache side-channel exposed by \u0027unwanted-reply-threshold\u0027",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "206fc3a0-e175-490b-9eaa-a5738056c9f6",
"assignerShortName": "NLnet Labs",
"cveId": "CVE-2026-109125",
"datePublished": "2026-10-21T08:56:35.696Z",
"dateReserved": "2026-10-14T09:16:14.087Z",
"dateUpdated": "2026-10-21T08:56:35.696Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2024-6129 (GCVE-0-2024-6129)
Vulnerability from cvelistv5 – Published: 2024-06-18 21:00 – Updated: 2024-08-19 18:08- CWE-205 - Observable Behavioral Discrepancy
| URL | Tags |
|---|---|
| https://vuldb.com/?id.268896 | vdb-entrytechnical-description |
| https://vuldb.com/?ctiid.268896 | signaturepermissions-required |
| https://seclists.org/fulldisclosure/2024/Jun/6 | mailing-list |
| https://msecureltd.blogspot.com/2024/04/friday-fu… | exploit |
| Vendor | Product | Version | |
|---|---|---|---|
| n/a | spa-cartcms |
Affected:
1.9.0.6
|
|
| spa-cart | spa-cart |
Affected:
1.9.0.6
cpe:2.3:a:spa-cart:spa-cart:1.9.0.6:*:*:*:*:*:*:* |
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-01T21:33:05.155Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"name": "VDB-268896 | spa-cartcms Username login observable behavioral discrepancy",
"tags": [
"vdb-entry",
"technical-description",
"x_transferred"
],
"url": "https://vuldb.com/?id.268896"
},
{
"name": "VDB-268896 | CTI Indicators (IOB, IOC, TTP, IOA)",
"tags": [
"signature",
"permissions-required",
"x_transferred"
],
"url": "https://vuldb.com/?ctiid.268896"
},
{
"tags": [
"mailing-list",
"x_transferred"
],
"url": "https://seclists.org/fulldisclosure/2024/Jun/6"
},
{
"tags": [
"exploit",
"x_transferred"
],
"url": "https://msecureltd.blogspot.com/2024/04/friday-fun-pentest-series-5-spa.html"
}
],
"title": "CVE Program Container"
},
{
"affected": [
{
"cpes": [
"cpe:2.3:a:spa-cart:spa-cart:1.9.0.6:*:*:*:*:*:*:*"
],
"defaultStatus": "unknown",
"product": "spa-cart",
"vendor": "spa-cart",
"versions": [
{
"status": "affected",
"version": "1.9.0.6"
}
]
}
],
"metrics": [
{
"other": {
"content": {
"id": "CVE-2024-6129",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-08-19T18:03:02.695390Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2024-08-19T18:08:42.112Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"modules": [
"Username Handler"
],
"product": "spa-cartcms",
"vendor": "n/a",
"versions": [
{
"status": "affected",
"version": "1.9.0.6"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "A vulnerability, which was classified as problematic, was found in spa-cartcms 1.9.0.6. Affected is an unknown function of the file /login of the component Username Handler. The manipulation of the argument email leads to observable behavioral discrepancy. It is possible to launch the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-268896."
},
{
"lang": "de",
"value": "Es wurde eine Schwachstelle in spa-cartcms 1.9.0.6 gefunden. Sie wurde als problematisch eingestuft. Hiervon betroffen ist ein unbekannter Codeblock der Datei /login der Komponente Username Handler. Dank Manipulation des Arguments email mit unbekannten Daten kann eine observable behavioral discrepancy-Schwachstelle ausgenutzt werden. Der Angriff kann \u00fcber das Netzwerk angegangen werden. Die Komplexit\u00e4t eines Angriffs ist eher hoch. Sie gilt als schwierig auszunutzen. Der Exploit steht zur \u00f6ffentlichen Verf\u00fcgung."
}
],
"metrics": [
{
"cvssV4_0": {
"baseScore": 6.3,
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
"version": "4.0"
}
},
{
"cvssV3_1": {
"baseScore": 3.7,
"baseSeverity": "LOW",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
}
},
{
"cvssV3_0": {
"baseScore": 3.7,
"baseSeverity": "LOW",
"vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"version": "3.0"
}
},
{
"cvssV2_0": {
"baseScore": 2.6,
"vectorString": "AV:N/AC:H/Au:N/C:P/I:N/A:N",
"version": "2.0"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-205",
"description": "CWE-205 Observable Behavioral Discrepancy",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2024-06-18T21:00:08.822Z",
"orgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
"shortName": "VulDB"
},
"references": [
{
"name": "VDB-268896 | spa-cartcms Username login observable behavioral discrepancy",
"tags": [
"vdb-entry",
"technical-description"
],
"url": "https://vuldb.com/?id.268896"
},
{
"name": "VDB-268896 | CTI Indicators (IOB, IOC, TTP, IOA)",
"tags": [
"signature",
"permissions-required"
],
"url": "https://vuldb.com/?ctiid.268896"
},
{
"tags": [
"mailing-list"
],
"url": "https://seclists.org/fulldisclosure/2024/Jun/6"
},
{
"tags": [
"exploit"
],
"url": "https://msecureltd.blogspot.com/2024/04/friday-fun-pentest-series-5-spa.html"
}
],
"timeline": [
{
"lang": "en",
"time": "2024-06-18T00:00:00.000Z",
"value": "Advisory disclosed"
},
{
"lang": "en",
"time": "2024-06-18T02:00:00.000Z",
"value": "VulDB entry created"
},
{
"lang": "en",
"time": "2024-06-18T18:27:34.000Z",
"value": "VulDB entry last update"
}
],
"title": "spa-cartcms Username login observable behavioral discrepancy"
}
},
"cveMetadata": {
"assignerOrgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
"assignerShortName": "VulDB",
"cveId": "CVE-2024-6129",
"datePublished": "2024-06-18T21:00:08.822Z",
"dateReserved": "2024-06-18T16:21:36.853Z",
"dateUpdated": "2024-08-19T18:08:42.112Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
CVE-2017-11155 (GCVE-0-2017-11155)
Vulnerability from cvelistv5 – Published: 2017-08-08 15:00 – Updated: 2024-09-17 00:46- CWE-205 - Information Exposure Through Behavioral Discrepancy (CWE-205)
| URL | Tags |
|---|---|
| https://www.synology.com/en-global/support/securi… | x_refsource_CONFIRM |
| https://www.exploit-db.com/exploits/42434/ | exploitx_refsource_EXPLOIT-DB |
| Vendor | Product | Version | |
|---|---|---|---|
| Synology | Synology Photo Station |
Affected:
before 6.7.3-3432 and 6.3-2967
|
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-05T17:57:58.052Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_CONFIRM",
"x_transferred"
],
"url": "https://www.synology.com/en-global/support/security/Synology_SA_17_34_PhotoStation"
},
{
"name": "42434",
"tags": [
"exploit",
"x_refsource_EXPLOIT-DB",
"x_transferred"
],
"url": "https://www.exploit-db.com/exploits/42434/"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "Synology Photo Station",
"vendor": "Synology",
"versions": [
{
"status": "affected",
"version": "before 6.7.3-3432 and 6.3-2967"
}
]
}
],
"datePublic": "2017-07-31T00:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "An information exposure vulnerability in index.php in Synology Photo Station before 6.7.3-3432 and 6.3-2967 allows remote attackers to obtain sensitive system information via unspecified vectors."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-205",
"description": "Information Exposure Through Behavioral Discrepancy (CWE-205)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2017-08-11T15:57:01.000Z",
"orgId": "db201096-a0cc-46c7-9a55-61d9e221bf01",
"shortName": "synology"
},
"references": [
{
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://www.synology.com/en-global/support/security/Synology_SA_17_34_PhotoStation"
},
{
"name": "42434",
"tags": [
"exploit",
"x_refsource_EXPLOIT-DB"
],
"url": "https://www.exploit-db.com/exploits/42434/"
}
],
"x_legacyV4Record": {
"CVE_data_meta": {
"ASSIGNER": "security@synology.com",
"DATE_PUBLIC": "2017-07-31T00:00:00",
"ID": "CVE-2017-11155",
"STATE": "PUBLIC"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "Synology Photo Station",
"version": {
"version_data": [
{
"version_value": "before 6.7.3-3432 and 6.3-2967"
}
]
}
}
]
},
"vendor_name": "Synology"
}
]
}
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "An information exposure vulnerability in index.php in Synology Photo Station before 6.7.3-3432 and 6.3-2967 allows remote attackers to obtain sensitive system information via unspecified vectors."
}
]
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "Information Exposure Through Behavioral Discrepancy (CWE-205)"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "https://www.synology.com/en-global/support/security/Synology_SA_17_34_PhotoStation",
"refsource": "CONFIRM",
"url": "https://www.synology.com/en-global/support/security/Synology_SA_17_34_PhotoStation"
},
{
"name": "42434",
"refsource": "EXPLOIT-DB",
"url": "https://www.exploit-db.com/exploits/42434/"
}
]
}
}
}
},
"cveMetadata": {
"assignerOrgId": "db201096-a0cc-46c7-9a55-61d9e221bf01",
"assignerShortName": "synology",
"cveId": "CVE-2017-11155",
"datePublished": "2017-08-08T15:00:00.000Z",
"dateReserved": "2017-07-10T00:00:00.000Z",
"dateUpdated": "2024-09-17T00:46:54.183Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
GHSA-66RC-377G-M4M4
Vulnerability from github – Published: 2026-10-21 09:30 – Updated: 2026-10-21 09:30In NLnet Labs Unbound up to and including version 1.26.1, an observable cache-level side-channel can be exposed with 'unwanted-reply-threshold > 0' configurations (not a default configuration). If a response-like UDP datagram reaches the upstream source port currently used by a recursive query, but its TXID does not match any pending query, Unbound counts the packet as an unwanted reply. When the accumulated count reaches the configured threshold, Unbound clears the worker's RRset cache and message cache. This cache clear action does not destroy the current upstream UDP pending query. Therefore, an external observer can distinguish whether a candidate port matches the current upstream source port by checking whether an existing cached item has been cleared. This is a cache side-channel vulnerability that can be used to probe the upstream source port. Although the attack is not feasible on default configurations and the suggested value (10 million) makes it an ureliable attack on a public resolver, in scenarios where the attacker can keep a concurrent query window alive, the attacker can first filter the source port and then perform birthday-style guessing against the TXID, making cache poisoning a feasible attack path.
{
"affected": [],
"aliases": [
"CVE-2026-109125"
],
"database_specific": {
"cwe_ids": [
"CWE-205"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-21T09:17:06Z",
"severity": "MODERATE"
},
"details": "In NLnet Labs Unbound up to and including version 1.26.1, an observable cache-level side-channel can be exposed with \u0027unwanted-reply-threshold \u003e 0\u0027 configurations (not a default configuration). If a response-like UDP datagram reaches the upstream source port currently used by a recursive query, but its TXID does not match any pending query, Unbound counts the packet as an unwanted reply. When the accumulated count reaches the configured threshold, Unbound clears the worker\u0027s RRset cache and message cache. This cache clear action does not destroy the current upstream UDP pending query. Therefore, an external observer can distinguish whether a candidate port matches the current upstream source port by checking whether an existing cached item has been cleared. This is a cache side-channel vulnerability that can be used to probe the upstream source port. Although the attack is not feasible on default configurations and the suggested value (10 million) makes it an ureliable attack on a public resolver, in scenarios where the attacker can keep a concurrent query window alive, the attacker can first filter the source port and then perform birthday-style guessing against the TXID, making cache poisoning a feasible attack path.",
"id": "GHSA-66rc-377g-m4m4",
"modified": "2026-10-21T09:30:30Z",
"published": "2026-10-21T09:30:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109125"
},
{
"type": "WEB",
"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-109125.txt"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-84MH-M38Q-M9VH
Vulnerability from github – Published: 2024-06-18 21:30 – Updated: 2024-11-18 16:26A vulnerability, which was classified as problematic, was found in spa-cartcms 1.9.0.6. Affected is an unknown function of the file /login of the component Username Handler. The manipulation of the argument email leads to observable behavioral discrepancy. It is possible to launch the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-268896.
{
"affected": [],
"aliases": [
"CVE-2024-6129"
],
"database_specific": {
"cwe_ids": [
"CWE-203",
"CWE-205"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-06-18T21:15:57Z",
"severity": "MODERATE"
},
"details": "A vulnerability, which was classified as problematic, was found in spa-cartcms 1.9.0.6. Affected is an unknown function of the file /login of the component Username Handler. The manipulation of the argument email leads to observable behavioral discrepancy. It is possible to launch the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-268896.",
"id": "GHSA-84mh-m38q-m9vh",
"modified": "2024-11-18T16:26:45Z",
"published": "2024-06-18T21:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-6129"
},
{
"type": "WEB",
"url": "https://msecureltd.blogspot.com/2024/04/friday-fun-pentest-series-5-spa.html"
},
{
"type": "WEB",
"url": "https://seclists.org/fulldisclosure/2024/Jun/6"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.268896"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.268896"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/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"
}
]
}
GHSA-8VH4-8CP7-H627
Vulnerability from github – Published: 2022-05-13 01:38 – Updated: 2025-04-20 03:42An information exposure vulnerability in index.php in Synology Photo Station before 6.7.3-3432 and 6.3-2967 allows remote attackers to obtain sensitive system information via unspecified vectors.
{
"affected": [],
"aliases": [
"CVE-2017-11155"
],
"database_specific": {
"cwe_ids": [
"CWE-200",
"CWE-205"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2017-08-08T15:29:00Z",
"severity": "HIGH"
},
"details": "An information exposure vulnerability in index.php in Synology Photo Station before 6.7.3-3432 and 6.3-2967 allows remote attackers to obtain sensitive system information via unspecified vectors.",
"id": "GHSA-8vh4-8cp7-h627",
"modified": "2025-04-20T03:42:42Z",
"published": "2022-05-13T01:38:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-11155"
},
{
"type": "WEB",
"url": "https://www.exploit-db.com/exploits/42434"
},
{
"type": "WEB",
"url": "https://www.synology.com/en-global/support/security/Synology_SA_17_34_PhotoStation"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
No mitigation information available for this CWE.
CAPEC-541: Application Fingerprinting
An adversary engages in fingerprinting activities to determine the type or version of an application installed on a remote target.
CAPEC-580: System Footprinting
An adversary engages in active probing and exploration activities to determine security information about a remote target system. Often times adversaries will rely on remote applications that can be probed for system configurations.