Heap-based buffer overflow in the IsPixelGray function in MagickCore/pixel-accessor.h in ImageMagick 7.0.3.8 allows remote attackers to cause a denial of service (out-of-bounds heap read) via a crafted image file. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-9556. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-9773
