{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-35042","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-03-31T21:06:06.428Z","datePublished":"2026-04-06T17:02:12.180Z","dateUpdated":"2026-04-07T15:59:49.872Z"},"containers":{"cna":{"title":"fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)","problemTypes":[{"descriptions":[{"cweId":"CWE-345","lang":"en","description":"CWE-345: Insufficient Verification of Data Authenticity","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-636","lang":"en","description":"CWE-636: Not Failing Securely ('Failing Open')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6","tags":["x_refsource_CONFIRM"],"url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6"},{"name":"https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11","tags":["x_refsource_MISC"],"url":"https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11"}],"affected":[{"vendor":"nearform","product":"fast-jwt","versions":[{"version":"<= 6.1.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-04-06T17:02:12.180Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-hm7r-c7qw-ghp6","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-07T15:19:36.239438Z","id":"CVE-2026-35042","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-04-07T15:59:49.872Z"}}]}}