The wpForo Forum WordPress plugin before 3.1.2 does not sanitize and escape a user profile field before outputting it inside an HTML attribute on the public participant profile page, allowing users with a subscriber-level account to inject JavaScript that executes in the browser of any visitor who views the profile, including a logged-in administrator.
https://wpscan.com/vulnerability/0dde2d89-267f-4aca-b2f0-d086b15adff0/