Multiple cross-site request forgery (CSRF) vulnerabilities in MyBB 1.2.11 and earlier allow remote attackers to (1) hijack the authentication of moderators or administrators for requests that delete threads via a do_multideletethreads action to moderation.php and (2) hijack the authentication of arbitrary users for requests that delete private messages (PM) via a delete action to private.php.
Cross-Site Request Forgery The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.