The WP Fastest Cache Premium plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 1.7.4 via the 'get_server_time_ajax_request' AJAX action. This makes it possible for authenticated attackers, with Subscriber-level access and above, to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services. The free version is not affected.