Improper Verification of Cryptographic Signature Affecting py3.12-pyjwt package, versions <2.14.0-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.18% (7th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-MINIMOSLATEST-PY312PYJWT-20342905
  • published1 Oct 2026
  • disclosed28 Sept 2026

Introduced: 28 Sep 2026

NewCVE-2026-102266  (opens in a new tab)
CWE-347  (opens in a new tab)

How to fix?

Upgrade Minimos:latest py3.12-pyjwt to version 2.14.0-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream py3.12-pyjwt package and not the py3.12-pyjwt package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.

CVSS Base Scores

version 3.1