The Keep Backup Daily plugin for WordPress is vulnerable to Limited Path Traversal in all versions up to, and including, 2.1.1 via the kbd_open_upload_dir AJAX action. This is due to insufficient validation of the kbd_path parameter, which is only sanitized with sanitize_text_field() - a function that does not strip path traversal sequences. This makes it possible for authenticated attackers, with Administrator-level access and above, to list the contents of arbitrary directories on the server outside of the intended uploads directory.