Description


fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.0, fast-jwt createVerifier accepts a validly signed JWT whose payload is a JSON array because src/decoder.js checks that the payload is an object but does not reject arrays. The claim validator loop then finds no named exp, nbf, iss, aud, sub, jti, or nonce properties and silently skips those configured checks, returning the array as a successfully verified payload. An attacker who can produce or influence a validly signed token may bypass expiry, issuer, audience, subject, revocation, and replay protections. The opt-in requiredClaims option can block missing claims, and signature verification itself is not bypassed. This issue is fixed in version 6.3.0.

Related CPE's


Could not find any relations

Weaknesses



CWE-1287

CVSS impact metrics


CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

8.1 · High

Information


Source identifier

[email protected]

Vulnerability status

Deferred

Published

2026-10-08T22:17:28.623Z

10 hours ago

Last modified

2026-10-08T22:17:28.757Z

10 hours ago