user/view.php in Moodle through 2.1.10, 2.2.x before 2.2.8, 2.3.x before 2.3.5, and 2.4.x before 2.4.2 does not enforce the forceloginforprofiles setting, which allows remote attackers to obtain sensitive course-profile information by leveraging the guest role, as demonstrated by a Google search.
https://moodle.org/mod/forum/discuss.php?d=225341
http://openwall.com/lists/oss-security/2013/03/25/2
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101358.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101310.html
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-37481