psi/zicc.c in Artifex Ghostscript before 9.26 allows remote attackers to bypass intended access restrictions because of a setcolorspace type confusion.
https://www.ghostscript.com/doc/9.26/History9.htm#Version9.26
https://www.debian.org/security/2018/dsa-4346
https://usn.ubuntu.com/3831-1/
https://semmle.com/news/semmle-discovers-severe-vulnerability-ghostscript-postscript-pdf
https://lists.debian.org/debian-lts-announce/2018/11/msg00036.html
https://bugs.ghostscript.com/show_bug.cgi?id=700169
https://access.redhat.com/errata/RHSA-2019:0229
https://access.redhat.com/errata/RHBA-2019:0327
http://www.securityfocus.com/bid/106154
http://git.ghostscript.com/?p=ghostpdl.git%3Bh=434753adbe8be5534bfb9b7d91746023e8073d16
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=67d760ab775dae4efe803b5944b0439aa3c0b04a