Not Failing Securely ('Failing Open')

Overview fast-jwt is a Fast JSON Web Token implementation Affected versions of this package are vulnerable to Not Failing Securely 'Failing Open' due to improper validation of the crit header parameter. An attacker can bypass intended authorization policies by crafting a signed token with unknown...

CVE-2025-59420

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.4, Authlib’s JWS verification accepts tokens that declare unknown critical header parameters crit, violating RFC 7515 “must‑understand” semantics. An attacker can craft a signed token with a critical...