coders/wpg.c in GraphicsMagick 1.3.26 allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted file, related to the AcquireCacheNexus function in magick/pixel_cache.c.
https://www.debian.org/security/2018/dsa-4321
https://usn.ubuntu.com/4248-1/
https://lists.debian.org/debian-lts-announce/2018/06/msg00009.html
https://lists.debian.org/debian-lts-announce/2017/11/msg00013.html
http://www.securityfocus.com/bid/101795
http://hg.code.sf.net/p/graphicsmagick/code/rev/fcd3ed3394f6
http://hg.code.sf.net/p/graphicsmagick/code/rev/e8086faa52d0
http://hg.code.sf.net/p/graphicsmagick/code/rev/75245a215fff
http://hg.code.sf.net/p/graphicsmagick/code/rev/3dc7b4e3779d
http://hg.code.sf.net/p/graphicsmagick/code/rev/2b7c826d36af
http://hg.code.sf.net/p/graphicsmagick/code/rev/2a21cda3145b
http://hg.code.sf.net/p/graphicsmagick/code/rev/1b9e64a8901e
http://hg.code.sf.net/p/graphicsmagick/code/rev/135bdcb88b8d