An issue was discovered in GraphicsMagick 1.3.26. A NULL pointer dereference vulnerability was found in the function ReadEnhMetaFile in coders/emf.c, which allows attackers to cause a denial of service via a crafted file.
https://lists.debian.org/debian-lts-announce/2018/03/msg00025.html
https://lists.debian.org/debian-lts-announce/2018/08/msg00002.html
https://sourceforge.net/p/graphicsmagick/bugs/475/