fast-jwt is vulnerable to JWT Algorithm Confusion. The vulnerability is caused by a missing validation on publicKeyPemMatcher constant defined in fast-jwt/src/crypto.js which is used to match all common PEM formats for public keys. An attacker can craft a malicious JWT token utilizing the HS256 algorithm, signed with the public RSA key of the victim application. This attack works only if the victim application utilizes a public key containing the BEGIN RSA PUBLIC KEY header and uses the RS256 algorithm with the JWT verify function called without explicitly providing an…Read More
JSON Web Token (JWT) Algorithm Confusion
