CVE-2026-102272

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.

This vulnerability is rated as an Important severity because successful exploitation permits an unauthenticated remote attacker to bypass authentication and forge valid tokens, though exploitation requires specific mixed-algorithm verification settings. In Red Hat environments, exposure is restricted to services that simultaneously allow both symmetric HMAC and asymmetric signature algorithms while parsing public keys that contain byte order marks. Workloads and services that enforce single-algorithm verification policies or utilize standard asymmetric key validation routines are not susceptible to this attack.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.