Multiple cross-site scripting (XSS) vulnerabilities in lib/conditionlib.php in Moodle 2.4.x before 2.4.5 and 2.5.x before 2.5.1 allow remote attackers to inject arbitrary web script or HTML via the conditional access rule value of a user field.
https://moodle.org/mod/forum/discuss.php?d=232501
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-37516