"Most active topic" can leak topic title of topics in password-protected forums

Let us suppose a user A, having the required permissions to access to a forum protected by a password without having it and a user B, who has the requred permissions and the password. We observe the following bug : if the user B has in its personal data posted the greater number of messages in a topic of this forum, the user A, without having the access to this forum as he does not know the password could see the name of this topic on the user B's profile."