Insufficient checks in a web service made it possible to add comments to the comments block on another user's dashboard when it was not otherwise available (e.g., on their profile page).
https://moodle.org/mod/forum/discuss.php?d=455641
https://bugzilla.redhat.com/show_bug.cgi?id=2264099
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-78300