In GraphicsMagick 1.4 snapshot-20191208 Q8, there is a heap-based buffer over-read in the function EncodeImage of coders/pict.c.
https://www.debian.org/security/2020/dsa-4640
https://sourceforge.net/p/graphicsmagick/bugs/617/
https://lists.debian.org/debian-lts-announce/2020/01/msg00029.html
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00064.html
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00026.html
http://hg.graphicsmagick.org/hg/GraphicsMagick/rev/28f8bacd4bbf