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 c…
Published: 2026-03-12 · CVSS: 7.5 · CVSS 3.1
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 it. This violates the MUST requirement in the RFC. This vulnerability is fixed in 2.12.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7