The xps_load_sfnt_name function in xps/xpsfont.c in Artifex Ghostscript GhostXPS 9.21 allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a crafted document.
https://security.gentoo.org/glsa/201811-12
http://www.securityfocus.com/bid/99993
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=3c2aebbedd37fab054e80f2e315de07d7e9b5bdb