VULNERABILITY INTELLIGENCE

CVE-2026-35042

CVSS score7.5 HIGH
EPSS probability0.15%
CISA KEVNot currently listed
Published2026-04-06
Last modified2026-10-24
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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.

Weakness classification

  • security-advisories@github.com: CWE-345

Primary references