The ExportAlphaQuantumType function in export.c in GraphicsMagick before 1.3.18 might allow remote attackers to cause a denial of service (crash) via vectors related to exporting the alpha of an 8-bit RGBA image.
https://bugzilla.redhat.com/show_bug.cgi?id=1019085
http://www.securityfocus.com/bid/63002
http://www.openwall.com/lists/oss-security/2013/11/15/14
http://security.gentoo.org/glsa/glsa-201311-10.xml
http://secunia.com/advisories/55721
http://secunia.com/advisories/55288
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00032.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-November/120008.html