CVE-2026-102268

9.1 CRITICALpublic exploit available

Published 2026-09-28 · Updated 2026-09-29

AI risk analysis

Summary: The flaw in PyJWT allows attackers to forge authenticated HMAC tokens by supplying a mutated public-key PEM as raw key bytes, leading to unauthorized access.
Exploitability: Exploitation is moderately hard as it requires knowledge of the public key and mixing of HMAC and asymmetric algorithms. Precondition is the use of an affected version of PyJWT in an application.
Blast radius: If exploited, the impact is high as it can lead to unauthorized access and potential data breaches.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to PyJWT 2.14.0 or later.

auth-bypassjwtpythonsecurity

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD 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.

CVSS vector

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

Weaknesses

CWE-347

Public exploit & PoC references

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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