WP Meta SEO <= 4.5.4 - Authenticated (Author+) PHAR Deserialization

The WP Meta SEO plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 4.5.4 due to insufficient file path validation that makes it possible for attackers to supply paths to files with a phar:// wrapper that will unserialize during retrieval. This makes it possible for authenticated attackers, with author-level permissions and above, to inject a PHP Object. The plugin does contain a useable gadget chain that may make remote execution possible.