The decode_frame function in the KVG1 decoder (kgv1dec.c) in libavcodec in FFmpeg 0.7.x before 0.7.12 and 0.8.x before 0.8.11, and in Libav 0.5.x before 0.5.9, 0.6.x before 0.6.6, 0.7.x before 0.7.5, and 0.8.x before 0.8.1, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted media file.
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.