Meta Box Plugin for WordPress: Authenticated (Contributor+) Arbitrary File Deletion via ajax_delete_file

The Meta Box plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the 'ajax_delete_file' function in all versions up to, and including, 5.11.1. 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).