reSmush.it Image Optimizer <= 0.4.6 - Cross-Site Request Forgery

The reSmush.it Image Optimizer plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 0.4.6. This is due to missing or incorrect nonce validation on several AJAX calls. This makes it possible for unauthenticated attackers to invoke those functions to do things like process images and delete/restore back-ups created by the pluign, via forged request granted they can trick a site administrator into performing an action such as clicking on a link.