The Registration, User Profile, Membership, Content Restriction, User Directory, and Frontend Post Submission – WP User Frontend plugin for WordPress is vulnerable to unauthorized loss of data due to a missing capability check on the 'Frontend_Form_Ajax::submit_post' function in all versions up to, and including, 4.2.4. This makes it possible for unauthenticated attackers to delete attachment.
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.2/includes/Ajax.php#L69
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.2/includes/Ajax.php#L25