MH-WikiBot (an IRC Bot for interacting with the Miraheze API), had a bug that allowed any unprivileged user to access the steward commands on the IRC...

MH-WikiBot (an IRC Bot for interacting with the Miraheze API), had a bug that allowed any unprivileged user to access the steward commands on the IRC interface by impersonating the Nickname used by a privileged user as no check was made to see if they were logged in. The issue has been fixed in commit 23d9d5b0a59667a5d6816fdabb960b537a5f9ed1.