The wpForo Forum WordPress plugin from 3.0.0 before 3.1.6 does not verify the source of client-supplied IP address headers before using them to key its per-visitor rate limit on paid AI requests, allowing unauthenticated attackers to bypass the limit by spoofing the header and exhaust the site owner's metered AI credits.
https://wpscan.com/vulnerability/1c08e9ba-b68a-4e77-970f-3dc7c7cd74f9/