The mem_get_bits_rectangle function in Artifex Software, Inc. Ghostscript 9.20 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted PostScript document.
https://security.gentoo.org/glsa/201708-06
https://bugs.ghostscript.com/show_bug.cgi?id=697676
https://access.redhat.com/errata/RHSA-2017:2180
http://www.securitytracker.com/id/1039071
http://www.securityfocus.com/bid/96995
http://www.ghostscript.com/cgi-bin/findgit.cgi?309eca4e0a31ea70dcc844812691439312dad091