GraphicsMagick 1.3.26 allows remote attackers to cause a denial of service (excessive memory allocation) because of an integer underflow in ReadPICTImage in coders/pict.c.
https://www.debian.org/security/2018/dsa-4321
https://usn.ubuntu.com/4232-1/
https://sourceforge.net/p/graphicsmagick/code/ci/0683f8724200495059606c03f04e0d589b33ebe8/
https://sourceforge.net/p/graphicsmagick/bugs/511/
https://lists.debian.org/debian-lts-announce/2018/08/msg00002.html
http://www.securityfocus.com/bid/101183
http://hg.graphicsmagick.org/hg/GraphicsMagick?cmd=changeset%3Bnode=0683f8724200