The WP Editor plugin for WordPress is vulnerable to deserialization of untrusted input via the 'current_theme_root' parameter in versions up to, and including 1.2.9. This makes it possible for authenticated attackers with administrative privileges to call files using a PHAR wrapper that will deserialize and call arbitrary PHP Objects that can be used to perform a variety of malicious actions granted a POP chain is also present. It also requires that the attacker is successful in uploading a file with the serialized payload.
