Ghostscript is vulnerable to denial of service(DoS) attacks. This is because the ghostscript device cleanup does not properly handle devices replaced with a null device. An attacker could possibly exploit this to bypass the -dSAFER protection and crash ghostscript or possibly execute arbitrary code in the ghostscript context via a specially crafted PostScript document.
git.ghostscript.com/?p=ghostpdl.git;a=commit;h=241d91112771a6104de10b3948c3f350d6690c1d
access.redhat.com/errata/RHSA-2018:3834
access.redhat.com/security/updates/classification/#important
bugs.ghostscript.com/show_bug.cgi?id=699664
bugzilla.redhat.com/show_bug.cgi?id=1657822
lists.debian.org/debian-lts-announce/2018/09/msg00015.html
security.gentoo.org/glsa/201811-12
usn.ubuntu.com/3768-1/
www.artifex.com/news/ghostscript-security-resolved/
www.debian.org/security/2018/dsa-4288