The Prime Mover – Backup and Migration plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 2.2.1 via deserialization of untrusted input in the migration search-and-replace routine (recursiveUnserializeReplace()). An unauthenticated attacker can store a crafted, base64-encoded serialized object in wp_comments.comment_content through the standard comment-submission endpoint (wp-comments-post.php). When an administrator subsequently performs a routine Prime Mover export or restore, the plugin base64-decodes that stored value and passes it to unserialize() with no allowed_classes restriction.
A Property-Oriented Programming (POP) chain is present in the plugin's own bundled Freemius library (FS_Clone_Manager::__set → FS_Option_Manager::set_option → store() → update_option()), so no additional plugin or theme is required — the plugin ships the gadget itself.
Attack Parameters
Impact Assessment
CVSS Vector v3.1