Key/algorithm type confusion

Description In Firebase PHP-JWT before 6.0.0, an algorithm-confusion issue (e.g., RS256 / HS256) exists via the kid (aka Key ID) header, when multiple types of keys are loaded in a key ring. This allows an attacker to forge tokens that validate under the incorrect key. NOTE: this provides a straightforward way to use the PHP-JWT library unsafely, but might not be considered a vulnerability in the library itself. References https://nvd.nist.gov/vuln/detail/CVE-2021-46743 firebase/php-jwt#351 https://github.com/firebase/php-jwt/releases/tag/v6.0.0 https://github.com/FriendsOfPHP/security-advisories/blob/master/firebase/php-jwt/CVE-2021-46743.yaml