A remote code execution risk was identified in the Lesson activity. By default this was only available to teachers and managers.
https://moodle.org/mod/forum/discuss.php?d=451580
https://bugzilla.redhat.com/show_bug.cgi?id=2243352
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-79408