Multiple cross-site request forgery (CSRF) vulnerabilities in user/messageselect.php in the messaging system in Moodle 2.2.x before 2.2.7, 2.3.x before 2.3.4, and 2.4.x before 2.4.1 allow remote attackers to hijack the authentication of arbitrary users for requests that send course messages.
https://moodle.org/mod/forum/discuss.php?d=220164
http://openwall.com/lists/oss-security/2013/01/21/1
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-36600