An unauthenticated privilege-escalation issue exists in the bbPress plugin before 2.6.5 for WordPress when New User Registration is enabled.
https://wordpress.org/plugins/bbpress/#developers
https://codex.bbpress.org/releases/
https://bbpress.org/blog/2020/05/bbpress-2-6-5-is-out/
http://packetstormsecurity.com/files/157885/WordPress-BBPress-2.5-Privilege-Escalation.html