The Database activity module in Moodle 2.1.x before 2.1.9, 2.2.x before 2.2.6, and 2.3.x before 2.3.3 allows remote attackers to bypass intended restrictions on reading other participants' entries via an advanced search.
https://moodle.org/mod/forum/discuss.php?d=216160
http://www.securityfocus.com/bid/56505
http://openwall.com/lists/oss-security/2012/11/19/1
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-35558