{"id":"CVE-2026-35042","revision":"f7b4f81d1ae04f5198cfc70170c1d340","records":[{"revision":"f7b4f81d1ae04f5198cfc70170c1d340","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-35042","aliases":[],"title":"fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)","description":"fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC.","state":0,"publishedAt":"2026-04-06T17:02:12.18+00:00","modifiedAt":"2026-04-07T15:59:49.872+00:00","affected":[{"ecosystem":"Vendor product","name":"fast-jwt","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"nearform\",\n                    \"product\": \"fast-jwt\",\n                    \"versions\": [\n                        {\n                            \"version\": \"<= 6.1.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5,"severity":"HIGH"}],"references":["https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6","https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-35042","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-35042","identifiers":["CVE-2026-35042"]},"retained":false,"historicalAffected":[]}],"coverage":[]}