The decode_ihdr_chunk function in libavcodec/pngdec.c in FFMpeg before 2.1.6, 2.2.x through 2.3.x, and 2.4.x before 2.4.4 allows remote attackers to cause a denial of service (out-of-bounds heap access) and possibly have other unspecified impact via an IDAT before an IHDR in a PNG file. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-9317
