In Artifex Ghostscript 9.23 before 2018-08-23, attackers are able to supply malicious PostScript files to bypass .tempfile restrictions and write files.
https://access.redhat.com/errata/RHSA-2018:3650
https://lists.debian.org/debian-lts-announce/2018/09/msg00015.html
https://security.gentoo.org/glsa/201811-12
https://usn.ubuntu.com/3768-1/