Bug 2542695 (CVE-2026-102272)

Summary:	CVE-2026-102272 pyjwt: pyjwt: Token forgery via improper Unicode byte-order mark handling
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in pyjwt. When verifying cryptographic keys, the raw JSON Web Key (JWK) parser fails to normalize Unicode byte-order marks (BOM). In mixed-algorithm verification environments, an attacker who knows the public key can supply a key prefixed with a byte-order mark, causing the system to misidentify the public key as a shared symmetric secret. This flaw allows an attacker to forge authenticated JSON Web Tokens (JWT) and bypass authentication controls.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-09-28 20:52:13 UTC

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.prepare_key in jwt/algorithms.py is affected because raw-JWK detector does not normalize accepted Unicode byte-order marks before checking for JSON. This occurs when a public JWK is prefixed with a UTF-8 BOM and used in a mixed-algorithm verification path. As a result, public JWK bypasses asymmetric-key detection and becomes the HMAC secret. Consequently, an attacker who knows the public key can forge authenticated tokens. This issue is fixed in version 2.14.0.