Artifex Ghostscript allows attackers to bypass a sandbox protection mechanism by leveraging exposure of system operators in the saved execution stack in an error object.
http://packetstormsecurity.com/files/149758/Ghostscript-Exposed-System-Operators.html
https://access.redhat.com/errata/RHSA-2018:3834
https://bugs.chromium.org/p/project-zero/issues/detail?id=1690
https://lists.debian.org/debian-lts-announce/2018/10/msg00013.html
https://usn.ubuntu.com/3803-1/