Podlove Podcast Publisher <= 4.5.3 - Authenticated (Contributor+) PHP Object Injection to Arbitrary File Deletion via 'unfurl_data' Parameter

The Podlove Podcast Publisher plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the create_link_item function in all versions up to, and including, 4.5.3. This makes it possible for authenticated attackers, with contributor-level access and above, to delete arbitrary files on the server, which can easily lead to remote code execution when the right file is deleted (such as wp-config.php). A viable POP chain exists within the plugin itself via Podlove\ImageCache\GenerationGuard, whose __destruct() method invokes wp_delete_file() with an attacker-controlled file path populated through unserialization.