{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-107724","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-10-08T17:21:52.976Z","datePublished":"2026-10-08T21:53:01.909Z","dateUpdated":"2026-10-08T21:53:01.909Z"},"containers":{"cna":{"title":"fast-jwt treats raw public JWK JSON as an HMAC secret, enabling HS256 token forgery","problemTypes":[{"descriptions":[{"cweId":"CWE-347","lang":"en","description":"CWE-347: Improper Verification of Cryptographic Signature","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-g3jj-5cmm-3hxx","tags":["x_refsource_CONFIRM"],"url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-g3jj-5cmm-3hxx"},{"name":"https://github.com/nearform/fast-jwt/pull/636","tags":["x_refsource_MISC"],"url":"https://github.com/nearform/fast-jwt/pull/636"},{"name":"https://github.com/nearform/fast-jwt/commit/10f9591349199ed2ab9fa1748ce92cdca697f6cf","tags":["x_refsource_MISC"],"url":"https://github.com/nearform/fast-jwt/commit/10f9591349199ed2ab9fa1748ce92cdca697f6cf"},{"name":"https://github.com/nearform/fast-jwt/releases/tag/v6.3.0","tags":["x_refsource_MISC"],"url":"https://github.com/nearform/fast-jwt/releases/tag/v6.3.0"}],"affected":[{"vendor":"nearform","product":"fast-jwt","versions":[{"version":">= 6.2.4, < 6.3.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-10-08T21:53:01.909Z"},"descriptions":[{"lang":"en","value":"fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.2.4, fast-jwt can classify raw serialized public JWK or JWKS JSON as an HMAC secret because src/crypto.js performDetectPublicKeyAlgorithms treats non-PEM strings as symmetric key material. If HS256 is explicitly allowed or inferred, an attacker who knows the exact serialized public-key bytes can use those bytes as an HMAC key and create a token containing arbitrary claims that createVerifier accepts. Serialization ordering or whitespace differences can prevent exploitation, and applications using supported PEM keys with an asymmetric-only algorithm allowlist are not affected. This issue is fixed in version 6.3.0."}],"source":{"advisory":"GHSA-g3jj-5cmm-3hxx","discovery":"UNKNOWN"}}}}