In GraphicsMagick from version 1.3.30 to 1.4 snapshot-20190403 Q8, there is a heap-based buffer overflow in the function WriteMATLABImage of coders/mat.c, which allows an attacker to cause a denial of service or possibly have unspecified other impact via a crafted image file. This is related to ExportRedQuantumType in magick/export.c.
https://www.debian.org/security/2020/dsa-4640
https://usn.ubuntu.com/4207-1/
https://sourceforge.net/p/graphicsmagick/bugs/604/
https://lists.debian.org/debian-lts-announce/2019/05/msg00027.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00057.html
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00055.html
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00021.html
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00020.html
http://hg.graphicsmagick.org/hg/GraphicsMagick/rev/57ac0ae85e2a