An issue was discovered in Artifex Ghostscript before 9.25. Incorrect “restoration of privilege” checking when running out of stack during exception handling could be used by attackers able to supply crafted PostScript to execute code using the “pipe” instruction. This is due to an incomplete fix for CVE-2018-16509.
git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=3e5d316b72e3965b7968bb1d96baa137cd063ac6
git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=643b24dbd002fb9c131313253c307cf3951b3d47
access.redhat.com/errata/RHSA-2018:3834
git.ghostscript.com/?p=ghostpdl.git%3Ba=commitdiff%3Bh=5812b1b78fc4d36fdc293b7859de69241140d590
lists.debian.org/debian-lts-announce/2018/09/msg00015.html
seclists.org/oss-sec/2018/q3/228
seclists.org/oss-sec/2018/q3/229
security.gentoo.org/glsa/201811-12
usn.ubuntu.com/3768-1/
www.debian.org/security/2018/dsa-4294