{"id":"CVE-2026-107720","revision":"1c256b755faf490abbb5181f7042d6c7","records":[{"revision":"1c256b755faf490abbb5181f7042d6c7","observedAt":"2026-10-25T05:17:13.11+00:00","statement":{"source":"nvd","id":"CVE-2026-107720","aliases":[],"title":"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 prepareKe…","description":"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.","state":0,"publishedAt":"2026-10-08T22:17:28.09+00:00","modifiedAt":"2026-10-09T15:17:08.947+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","score":7.4,"severity":"HIGH"}],"references":["https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534","https://github.com/nearform/fast-jwt/pull/649","https://github.com/nearform/fast-jwt/releases/tag/v6.3.1","https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-107720","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-20","CWE-347"],"productCriteria":[],"sourceDates":{"published":"2026-10-08T22:17:28.090","lastModified":"2026-10-09T15:17:08.947"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-107720","identifiers":["CVE-2026-107720"]},"retained":false,"historicalAffected":[]}],"coverage":[]}