PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be substituted. This issue is fixed in version 2.14.0.