CVEvulnerability

CVE-2026-102268

9.1 CRITICAL Published 2026-09-28 Modified 2026-10-07 Official page ↗
Status
Analyzed
Published
2026-09-28
Last modified
2026-10-07
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-347

Description

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.

Affected configurations

• pyjwt project pyjwt (< 2.14.0)

Related

Weakness · CWE (1)

  • CWE-347 Improper Verification of Cryptographic Signature weakness

References