The User Sync – Remote User Sync plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.0.2. This is due to missing or incorrect nonce validation on the mo_user_sync_form_handler() function. This makes it possible for unauthenticated attackers to deactivate the plugin via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.