The Icon List Block – Add Icon-Based Lists with Custom Styles plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 1.2.1 via the fs_api_request function. 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. Only valid JSON objects are rendered in the response.