Cross-site scripting (XSS) vulnerability in the get_description function in lib/classes/event/user_login_failed.php in Moodle 2.7.x before 2.7.1 allows remote attackers to inject arbitrary web script or HTML via a crafted username that is improperly handled during the logging of an invalid login attempt.
https://moodle.org/mod/forum/discuss.php?d=264271
http://www.securityfocus.com/bid/68761
http://openwall.com/lists/oss-security/2014/07/21/1
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-46201