CVE-2026-9679
Impact: undici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equivalents. RFC 6265 §5.4 does not specify any decoding and browsers do not decode either.
Applications that parse a Set-Cookie header and then forward the parsed value into a response header (proxies, middleware, SSR frameworks) become vulnerable to HTTP response header injection: an attacker-controlled upstream can inject arbitrary Set-Cookie, Location, or Cache-Control headers into the application's downstream response, enabling session fixation, open redirect, or cache poisoning.
Leer descripción completaMostrar menos
Affected applications are those that use undici's cookie parsing (parseSetCookie, parseCookie, getSetCookies) and forward the parsed cookie value into a response header.
This was introduced in undici 7.0.0 via PR #3789.
Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0.
Workarounds: If upgrade is not immediately possible, do not forward values returned by parseSetCookie/parseCookie/getSetCookies directly into response headers; sanitize the value first to strip or reject CR, LF, NUL, ;, and = bytes.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- Puntuación base: 5.9
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.33%
- Percentil entre todas las CVEs puntuadas: 24
- Fecha de la puntuación: 4/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-93
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-9679",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-9679",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-06-17T18:31:46.100353Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 5.9,
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "HIGH",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 2.2
}
]
},
"affected": [
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"affectedData": [
{
"vendor": "undici",
"product": "undici",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "6.26.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.26.0",
"versionType": "semver"
},
{
"status": "affected",
"version": "7.0.0",
"lessThan": "7.28.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.28.0",
"versionType": "semver"
},
{
"status": "affected",
"version": "8.0.0",
"lessThan": "8.5.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "8.5.0",
"versionType": "semver"
}
],
"packageURL": "pkg:npm/undici",
"defaultStatus": "unaffected"
}
]
}
],
"published": "2026-06-17T18:18:06.307",
"references": [
{
"url": "https://cna.openjsf.org/security-advisories.html",
"tags": [
"Vendor Advisory"
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb"
},
{
"url": "https://github.com/nodejs/undici/security/advisories/GHSA-p88m-4jfj-68fv",
"tags": [
"Vendor Advisory",
"Mitigation"
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb"
}
],
"vulnStatus": "Analyzed",
"weaknesses": [
{
"type": "Secondary",
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"description": [
{
"lang": "en",
"value": "CWE-93"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Impact:\nundici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equivalents. RFC 6265 §5.4 does not specify any decoding and browsers do not decode either.\n\nApplications that parse a Set-Cookie header and then forward the parsed value into a response header (proxies, middleware, SSR frameworks) become vulnerable to HTTP response header injection: an attacker-controlled upstream can inject arbitrary Set-Cookie, Location, or Cache-Control headers into the application's downstream response, enabling session fixation, open redirect, or cache poisoning.\n\nAffected applications are those that use undici's cookie parsing (parseSetCookie, parseCookie, getSetCookies) and forward the parsed cookie value into a response header.\n\nThis was introduced in undici 7.0.0 via PR #3789.\n\nPatches:\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\n\nWorkarounds:\nIf upgrade is not immediately possible, do not forward values returned by parseSetCookie/parseCookie/getSetCookies directly into response headers; sanitize the value first to strip or reject CR, LF, NUL, ;, and = bytes."
}
],
"lastModified": "2026-06-25T17:43:39.240",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "632BE4D6-A743-4F05-9B3F-FE6A7B3E58D2",
"versionEndExcluding": "6.27.0"
},
{
"criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "0C34D757-BB16-4E28-95D8-7D3FAC851B69",
"versionEndExcluding": "7.28.0",
"versionStartIncluding": "7.0.0"
},
{
"criteria": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
"vulnerable": true,
"matchCriteriaId": "37F3655C-C7AE-4B13-A5EB-6FE0A9566124",
"versionEndExcluding": "8.5.0",
"versionStartIncluding": "8.0.0"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb"
}