The Clearfy Cache – WordPress optimization plugin, Minify HTML, CSS & JS, Defer plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.3.1. This is due to missing or incorrect nonce validation on the wclearfy_cache_delete functionality . This makes it possible for unauthenticated attackers to clear the cache via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.