Several widely-used JSON Web Token (JWT) libraries, including node-jsonwebtoken, pyjwt, namshi/jose, php-jwt, and jsjwt, are affected by critical vulnerabilities that could allow attackers to bypass the verification step when using asymmetric keys (RS256, RS384, RS512, ES256, ES384, ES512).

References

• https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries
• https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries
• https://github.com/FriendsOfPHP/security-advisories/blob/master/gree/jose/2016-08-30.yaml