CVE-2026-107720
highfast-jwt provides fast JSON Web Token (JWT) implementation.
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534 security-advisories@github.com
- https://github.com/nearform/fast-jwt/pull/649 security-advisories@github.com
- https://github.com/nearform/fast-jwt/releases/tag/v6.3.1 security-advisories@github.com
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv security-advisories@github.com
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxv 134c704f-9b21-4f2e-91b3-4a467353bcc0