Artifex Ghostscript before 9.25 allowed a user-writable error exception table, which could be used by remote attackers able to supply crafted PostScript to potentially overwrite or replace error handlers to inject code.
https://usn.ubuntu.com/3773-1/
https://lists.debian.org/debian-lts-announce/2018/09/msg00038.html
https://bugs.ghostscript.com/show_bug.cgi?id=699708
https://access.redhat.com/errata/RHSA-2018:3834
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=fb713b3818b52d8a6cf62c951eba2e1795ff9624