The Modular DS: Monitor, update, and backup multiple websites plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.5.1. This is due to missing nonce validation on the postConfirmOauth() function. This makes it possible for unauthenticated attackers to disconnect the plugin's OAuth/SSO connection via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.