The Anti-Spam, Spam FireWall by CleanTalk WordPress plugin before 6.91 does not escape a commenter-supplied value before outputting it on an administrative spam-review screen, allowing unauthenticated users to inject arbitrary web scripts that execute in the browser of an administrator who reviews flagged comments.
https://wpscan.com/vulnerability/087d91ac-2158-4f9b-8fab-4d17b14a7053/