The Post Duplicator plugin for WordPress is vulnerable to unauthorized arbitrary protected post meta insertion in all versions up to, and including, 3.0.8. This is due to the `duplicate_post()` function in `includes/api.php` using `$wpdb->insert()` directly to the `wp_postmeta` table instead of WordPress's standard `add_post_meta()` function, which would call `is_protected_meta()` to …