Improper Verification of Cryptographic Signature Affecting python3-jwt package, versions <0:2.4.0-1.amzn2023.0.6


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.24% (15th percentile)

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  • Snyk IDSNYK-AMZN2023-PYTHON3JWT-21702779
  • published25 Oct 2026
  • disclosed28 Sept 2026

Introduced: 28 Sep 2026

CVE-2026-102268  (opens in a new tab)
CWE-347  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 python3-jwt to version 0:2.4.0-1.amzn2023.0.6 or higher.
This issue was patched in ALAS2023-2026-3298.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python3-jwt package and not the python3-jwt package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1