In ImageMagick 7.0.6-6 and GraphicsMagick 1.3.26, a heap-based buffer over-read was found in the function SFWScan in coders/sfw.c, which allows attackers to cause a denial of service via a crafted file.
https://github.com/ImageMagick/ImageMagick/issues/670
https://lists.debian.org/debian-lts-announce/2017/11/msg00016.html
https://lists.debian.org/debian-lts-announce/2018/06/msg00009.html
https://security.gentoo.org/glsa/201711-07
https://usn.ubuntu.com/3681-1/
https://usn.ubuntu.com/4222-1/
https://www.debian.org/security/2017/dsa-4032