{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-107720","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-10-08T17:21:52.975Z","datePublished":"2026-10-08T21:44:06.843Z","dateUpdated":"2026-10-09T14:32:14.931Z"},"containers":{"cna":{"title":"fast-jwt: createVerifier accepts unsigned JWTs when key is '' or null and algorithms is explicitly set","problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","description":"CWE-20: Improper Input Validation","type":"CWE"}]},{"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-8wpc-h4q6-8fxv","tags":["x_refsource_CONFIRM"],"url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv"},{"name":"https://github.com/nearform/fast-jwt/pull/649","tags":["x_refsource_MISC"],"url":"https://github.com/nearform/fast-jwt/pull/649"},{"name":"https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534","tags":["x_refsource_MISC"],"url":"https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534"},{"name":"https://github.com/nearform/fast-jwt/releases/tag/v6.3.1","tags":["x_refsource_MISC"],"url":"https://github.com/nearform/fast-jwt/releases/tag/v6.3.1"}],"affected":[{"vendor":"nearform","product":"fast-jwt","versions":[{"version":"< 6.3.1","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-10-08T21:44:06.843Z"},"descriptions":[{"lang":"en","value":"fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is false, and the empty signature avoids the verifySignature gate. An attacker can therefore submit a token containing arbitrary claims without possessing a signing key, resulting in authentication or authorization bypass. Claim validators still run, and non-empty keys, an empty key without algorithms, and the async key resolver path do not have this behavior. This issue is fixed in version 6.3.1."}],"source":{"advisory":"GHSA-8wpc-h4q6-8fxv","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-09T14:31:56.862139Z","id":"CVE-2026-107720","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-10-09T14:32:14.931Z"}}]}}