pyjwt: PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

A missing verification step has been discovered in PyJWT. PyJWT 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 PyJWT does not understand, the library accepts the token instead of rejecting it. This...

pyjwt: PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

A missing verification step has been discovered in PyJWT. PyJWT 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 PyJWT does not understand, the library accepts the token instead of rejecting it. This...

pyjwt: PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

A missing verification step has been discovered in PyJWT. PyJWT 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 PyJWT does not understand, the library accepts the token instead of rejecting it. This...

GHSA-752W-5FWX-JX9F PyJWT accepts unknown `crit` header extensions

Summary PyJWT 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 PyJWT does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC. This is t...

CVE-2026-32597

A missing verification step has been discovered in PyJWT. PyJWT 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 PyJWT does not understand, the library accepts the token instead of rejecting it. This...

CVE-2026-32597 PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT 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 PyJWT does not understand, the library accepts the token instead of rejecting...

CVE-2025-59420

Authlib (Python) prior to 1.6.4 verifies JWS tokens with unknown critical header parameters (crit), violating RFC 7515 must-understand semantics. An attacker could craft a signed token that strict verifiers reject but Authlib accepts, enabling policy bypass, replay, or privilege escalation in mix...