mod/forum/user.php in Moodle 1.9.x before 1.9.14, 2.0.x before 2.0.5, and 2.1.x before 2.1.2 allows remote authenticated users to discover the names of other users via unspecified vectors.
Weaknesses in this category are related to the management of permissions, privileges, and other security features that are used to perform access control.