The ff_MPV_frame_start function in libavcodec/mpegvideo.c in FFmpeg before 0.11 allows remote attackers to cause a denial of service (memory corruption) via unspecified vectors, related to starting "a frame outside SETUP state."
http://www.securityfocus.com/bid/55355
http://www.openwall.com/lists/oss-security/2012/09/02/4
http://www.openwall.com/lists/oss-security/2012/08/31/3
http://secunia.com/advisories/50468
http://git.videolan.org/?p=ffmpeg.git%3Ba=commitdiff%3Bh=59a4b73531428d2f420b4dad545172c8483ced0f