An issue was discovered in Artifex Ghostscript before 9.24. Incorrect "restoration of privilege" checking during handling of /invalidaccess exceptions could be used by attackers able to supply crafted PostScript to execute code using the "pipe" instruction.
https://www.exploit-db.com/exploits/45369/
https://www.debian.org/security/2018/dsa-4294
https://www.artifex.com/news/ghostscript-security-resolved/
https://usn.ubuntu.com/3768-1/
https://security.gentoo.org/glsa/201811-12
https://lists.debian.org/debian-lts-announce/2018/09/msg00015.html
https://bugs.ghostscript.com/show_bug.cgi?id=699654
https://access.redhat.com/errata/RHSA-2018:3760
https://access.redhat.com/errata/RHSA-2018:2918
http://www.securityfocus.com/bid/105122
http://seclists.org/oss-sec/2018/q3/142
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=79cccf641486a6595c43f1de1cd7ade696020a31
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=78911a01b67d590b4a91afac2e8417360b934156
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=5516c614dc33662a2afdc377159f70218e67bde5