CVE-2026-35042

Description

fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC.

CVSS Vector

References

• https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6
• https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11