FKIE_CVE-2026-11525
Vulnerability from fkie_nvd - Published: 2026-06-17 18:17 - Updated: 2026-06-25 17:46
Severity
Summary
Impact:
When undici parses a Set-Cookie header, it accepts any SameSite attribute value that contains Strict, Lax, or None as a substring, rather than the case-insensitive exact match specified by RFC 6265. Non-spec values are silently mapped to one of the three standard tokens. For example, SameSite=NoneOfYourBusiness is parsed as None (the most permissive setting), and SameSite=StrictLax is parsed as Lax (a downgrade from Strict).
Affected applications are those that consume Set-Cookie headers from server responses (for example via undici's fetch or proxy code paths) and then forward or rely on the parsed sameSite attribute. A malicious or non-compliant server can coerce the consumer's view of a cookie's SameSite policy to a weaker value, silently degrading the SameSite enforcement the cookie is supposed to provide.
This was introduced in undici 5.15.0 when the cookies feature was added.
Patches:
Upgrade to undici v6.26.0, v7.28.0 or v8.5.0.
Workarounds:
After parsing a Set-Cookie header, validate that the resulting sameSite attribute is one of 'Strict', 'Lax', or 'None' (exact, case-insensitive) before forwarding or relying on it.
References
| URL | Tags | ||
|---|---|---|---|
| ce714d77-add3-4f53-aff5-83d477b104bb | https://cna.openjsf.org/security-advisories.html | Vendor Advisory | |
| ce714d77-add3-4f53-aff5-83d477b104bb | https://github.com/nodejs/undici/security/advisories/GHSA-g8m3-5g58-fq7m | Mitigation, Vendor Advisory |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/undici",
"product": "undici",
"vendor": "undici",
"versions": [
{
"lessThan": "6.26.0",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.26.0",
"versionType": "semver"
},
{
"lessThan": "7.28.0",
"status": "affected",
"version": "7.0.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.28.0",
"versionType": "semver"
},
{
"lessThan": "8.5.0",
"status": "affected",
"version": "8.0.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "8.5.0",
"versionType": "semver"
}
]
}
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
"matchCriteriaId": "632BE4D6-A743-4F05-9B3F-FE6A7B3E58D2",
"versionEndExcluding": "6.27.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
"matchCriteriaId": "0C34D757-BB16-4E28-95D8-7D3FAC851B69",
"versionEndExcluding": "7.28.0",
"versionStartIncluding": "7.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
"matchCriteriaId": "37F3655C-C7AE-4B13-A5EB-6FE0A9566124",
"versionEndExcluding": "8.5.0",
"versionStartIncluding": "8.0.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Impact:\nWhen undici parses a Set-Cookie header, it accepts any SameSite attribute value that contains Strict, Lax, or None as a substring, rather than the case-insensitive exact match specified by RFC 6265. Non-spec values are silently mapped to one of the three standard tokens. For example, SameSite=NoneOfYourBusiness is parsed as None (the most permissive setting), and SameSite=StrictLax is parsed as Lax (a downgrade from Strict).\n\nAffected applications are those that consume Set-Cookie headers from server responses (for example via undici\u0027s fetch or proxy code paths) and then forward or rely on the parsed sameSite attribute. A malicious or non-compliant server can coerce the consumer\u0027s view of a cookie\u0027s SameSite policy to a weaker value, silently degrading the SameSite enforcement the cookie is supposed to provide.\n\nThis was introduced in undici 5.15.0 when the cookies feature was added.\n\nPatches:\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\n\nWorkarounds:\nAfter parsing a Set-Cookie header, validate that the resulting sameSite attribute is one of \u0027Strict\u0027, \u0027Lax\u0027, or \u0027None\u0027 (exact, case-insensitive) before forwarding or relying on it."
}
],
"id": "CVE-2026-11525",
"lastModified": "2026-06-25T17:46:21.653",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 3.7,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.2,
"impactScore": 1.4,
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-11525",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-17T17:53:40.763762Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-06-17T18:17:35.097",
"references": [
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"tags": [
"Vendor Advisory"
],
"url": "https://cna.openjsf.org/security-advisories.html"
},
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"tags": [
"Mitigation",
"Vendor Advisory"
],
"url": "https://github.com/nodejs/undici/security/advisories/GHSA-g8m3-5g58-fq7m"
}
],
"sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-183"
}
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"type": "Secondary"
}
]
}
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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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