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."
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.