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
https://euvd.enisa.europa.eu/vulnerability/EUVD-2012-5398
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