| Description |
This update addresses the following issue:
* The `invalid_strings` check in `HMACAlgorithm.prepare_key` does not account
for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format
would be allowed because it is prefaced with the string `-----BEGIN RSA
PUBLIC KEY-----` which is not accounted for. This enables
symmetric/asymmetric key confusion attacks against users using the PKCS1
PEM encoded public keys, which would allow an attacker to craft JWTs from
scratch. (CVE-2017-11424) |
