The vulnerability was found in Moodle, occurs due to improper input validation when parsing PostScript code. An omitted execution parameter results in a remote code execution risk for sites running GhostScript versions older than 9.50. Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
https://moodle.org/mod/forum/discuss.php?d=436456
https://bugzilla.redhat.com/show_bug.cgi?id=2106273
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-75044