GraphicsMagick 1.3.26 is vulnerable to a memory information disclosure vulnerability found in the DescribeImage function of the magick/describe.c file, because of a heap-based buffer over-read. The portion of the code containing the vulnerability is responsible for printing the IPTC Profile information contained in the image. This vulnerability can be triggered with a specially crafted MIFF file. There is an out-of-bounds buffer dereference because certain increments are never checked.
https://www.debian.org/security/2018/dsa-4321
https://usn.ubuntu.com/4232-1/
https://lists.debian.org/debian-lts-announce/2018/06/msg00009.html
https://lists.debian.org/debian-lts-announce/2017/11/msg00002.html
http://www.securityfocus.com/bid/101653
http://hg.graphicsmagick.org/hg/GraphicsMagick?cmd=changeset%3Bnode=e4e1c2a581d8