cxf: OpenId Connect token service does not properly validate the clientId
Apache CXF ships with a OpenId Connect JWK Keys service, which allows a client to obtain the public keys in JWK format, which can then be used to verify the signature of tokens issued by the service. Typically, the service obtains the public key from a local keystore (JKS/PKCS12) by specifing the path of the keystore and the alias of the keystore entry. This case is not vulnerable. However it is also possible to obtain the keys from a JWK keystore file, by setting the configuration parameter "rs.security.keystore.type" to "jwk". For this case all keys are returned in this file "as is", including all private key and secret key credentials. This is an obvious security risk if the user has configured the signature keystore file with private or secret key credentials. From CXF 3.3.5 and 3.2.12, it is mandatory to specify an alias corresponding to the id of the key in the JWK file, and only this key is returned. In addition, any private key information is omitted by default. "oct" keys, which contain secret keys, are not returned at all.