The ReadSUNImage function in coders/sun.c in GraphicsMagick 1.3.26 has a colormap heap-based buffer over-read.
hg.code.sf.net/p/graphicsmagick/code/rev/95d00d55e978
www.securityfocus.com/bid/100442
blogs.gentoo.org/ago/2017/08/05/graphicsmagick-heap-based-buffer-overflow-in-readsunimage-sun-c/
lists.debian.org/debian-lts-announce/2018/06/msg00009.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PF62B5PJA2JDUOCKJGUQO3SPL74BEYSV/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WHIKB4TP6KBJWT2UIPWL5MWMG5QXKGEJ/
usn.ubuntu.com/4222-1/
www.debian.org/security/2018/dsa-4321