The Advanced Database Cleaner plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.1.3 via deserialization of untrusted input in the 'process_bulk_action' function. This makes it possible for authenticated attacker, with administrator access and above, to inject a PHP Object. No POP chain is present in the vulnerable plugin. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.