CVE-2026-32597 HIGH

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

Vendor Jpadilla
Product pyjwt
Weakness CWE-345
Published March 12, 2026
Last update June 30, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 12, 2026 CVE published
June 30, 2026 Record updated