The stored-XSS vulnerability was discovered in Moodle which exists due to insufficient sanitization of user-supplied data in several "social" user profile fields. An attacker could inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
https://moodle.org/mod/forum/discuss.php?d=440771
https://bugzilla.redhat.com/show_bug.cgi?id=2142774
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-76131