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.
https://www.debian.org/security/2018/dsa-4336
https://usn.ubuntu.com/3803-1/
https://lists.debian.org/debian-lts-announce/2018/10/msg00013.html
https://bugs.ghostscript.com/show_bug.cgi?id=699927
https://bugs.chromium.org/p/project-zero/issues/detail?id=1690
https://access.redhat.com/errata/RHSA-2018:3834
http://www.openwall.com/lists/oss-security/2018/10/10/12
http://packetstormsecurity.com/files/149758/Ghostscript-Exposed-System-Operators.html
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=34cc326eb2c5695833361887fe0b32e8d987741c