{"attribution":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","cve":{"id":"CVE-2026-11525","sourceIdentifier":"ce714d77-add3-4f53-aff5-83d477b104bb","published":"2026-06-17T18:17:35.097","lastModified":"2026-06-25T17:46:21.653","vulnStatus":"Analyzed","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'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.\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 'Strict', 'Lax', or 'None' (exact, case-insensitive) before forwarding or relying on it."}],"affected":[{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","affectedData":[{"vendor":"undici","product":"undici","defaultStatus":"unaffected","packageURL":"pkg:npm/undici","versions":[{"version":"0","lessThan":"6.26.0","versionType":"semver","status":"affected"},{"version":"6.26.0","versionType":"semver","status":"unaffected"},{"version":"7.0.0","lessThan":"7.28.0","versionType":"semver","status":"affected"},{"version":"7.28.0","versionType":"semver","status":"unaffected"},{"version":"8.0.0","lessThan":"8.5.0","versionType":"semver","status":"affected"},{"version":"8.5.0","versionType":"semver","status":"unaffected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":3.7,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":2.2,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-06-17T17:53:40.763762Z","id":"CVE-2026-11525","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","type":"Secondary","description":[{"lang":"en","value":"CWE-183"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*","versionEndExcluding":"6.27.0","matchCriteriaId":"632BE4D6-A743-4F05-9B3F-FE6A7B3E58D2"},{"vulnerable":true,"criteria":"cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*","versionStartIncluding":"7.0.0","versionEndExcluding":"7.28.0","matchCriteriaId":"0C34D757-BB16-4E28-95D8-7D3FAC851B69"},{"vulnerable":true,"criteria":"cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*","versionStartIncluding":"8.0.0","versionEndExcluding":"8.5.0","matchCriteriaId":"37F3655C-C7AE-4B13-A5EB-6FE0A9566124"}]}]}],"references":[{"url":"https://cna.openjsf.org/security-advisories.html","source":"ce714d77-add3-4f53-aff5-83d477b104bb","tags":["Vendor Advisory"]},{"url":"https://github.com/nodejs/undici/security/advisories/GHSA-g8m3-5g58-fq7m","source":"ce714d77-add3-4f53-aff5-83d477b104bb","tags":["Mitigation","Vendor Advisory"]}]}}