Forem: Stored XSS in Admin Abuse Report Rendering

Summary

Forem is open source software for building communities. In versions before commit 92eacd16a82cf9007ba8e16a2258b42e3b53ca9c, a malicious value submitted through feedback_message[message] is stored without sanitization and rendered in app/views/admin/feedback_messages/_feedback_message.html.erb through raw(feedback_message.message) when offender_id is present. Viewing the abuse report executes arbitrary JavaScript in an administrator's browser and may expose sensitive in-page data, abuse CSRF tokens, or perform administrative actions in the victim's session. The public FeedbackMessagesController accepts the report without authorization and previously permitted a submitted offender_id, making the vulnerable rendering path reachable by an unauthenticated attacker. This issue is fixed in commit 92eacd16a82cf9007ba8e16a2258b42e3b53ca9c