CVE-2026-11525
- Source
- https://cve.org/CVERecord?id=CVE-2026-11525
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11525.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-11525
- Aliases
- Downstream
- Related
- Published
- 2026-06-17T17:31:03.163Z
- Modified
- 2026-07-09T10:14:53.630768654Z
- Severity
-
- 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
- Summary
- undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching
- Details
-
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.
- Database specific
{ "cna_assigner": "openjs", "cwe_ids": [ "CWE-183" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/11xxx/CVE-2026-11525.json" }- References
Affected packages
Git / github.com/nodejs/undici
Affected ranges
- Type
- GIT
- Repo
- https://github.com/nodejs/undici
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedFixedIntroducedFixedIntroducedFixed
- Database specific
{ "extracted_events": [ { "introduced": "0" }, { "fixed": "6.27.0" }, { "introduced": "7.0.0" }, { "fixed": "7.28.0" }, { "introduced": "8.0.0" }, { "fixed": "8.5.0" } ], "cpe": "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*", "source": "CPE_RANGE" }