The reSmush.it : the only free Image Optimizer & compress plugin WordPress plugin before 0.4.4 lacks authorization in various AJAX actions, allowing any logged-in users, such as subscribers to call them.

The reSmush.it : the only free Image Optimizer & compress plugin WordPress plugin before 0.4.4 does not perform CSRF checks for any of its AJAX actions, allowing an attackers to trick logged in users to perform various actions on their behalf on the site.

The reSmush.it WordPress plugin before 0.4.6 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when unfiltered_html is disallowed.