course/reset.php in Moodle 2.1.x before 2.1.8, 2.2.x before 2.2.5, and 2.3.x before 2.3.2 checks an update capability instead of a reset capability, which allows remote authenticated users to bypass intended access restrictions via a reset operation.
http://openwall.com/lists/oss-security/2012/09/17/1
http://moodle.org/mod/forum/discuss.php?d=211558
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-34519