CVE-2026-102273

A flaw was found in PyJWT. This vulnerability allows an unauthenticated remote attacker to bypass authentication by forging arbitrary JSON Web Tokens (JWTs). When an application allows both symmetric and asymmetric algorithms, PyJWT fails to properly validate public JSON Web Key (JWK) container representations, mistakenly accepting public key material as a symmetric Hash-based Message Authentication Code (HMAC) secret. As a result, an attacker with knowledge of the public key can generate validly signed tokens with arbitrary authenticated claims.

Red Hat rates this vulnerability as Important because an attacker with access to a public verification key can forge cryptographic tokens to bypass authentication, allowing impersonation of privileged users and unauthorized access to protected application resources. Exploitation is limited to environments where applications concurrently permit symmetric HMAC and asymmetric algorithms while passing public key containers into validation routines.

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.