Moodle 2.0.x before 2.0.7 and 2.1.x before 2.1.4, when an anonymous front-page forum is enabled, allows remote attackers to obtain session keys for their sessions by visiting the front page.
https://bugzilla.redhat.com/show_bug.cgi?id=783532
http://moodle.org/mod/forum/discuss.php?d=194018
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-27334