Deactivate and delete. Notification on Envato repository: "This item is no longer available".
CraCkEr discovered and reported this Cross Site Scripting (XSS) vulnerability in WordPress Forym Plugin. This could allow a malicious actor to inject malicious scripts, such as redirects, advertisements, and other HTML payloads into your website which will be executed when guests visit your site. This vulnerability has not been known to be fixed yet.