The vqa_decode_chunk function in libavcodec/vqavideo.c in FFmpeg before 1.0.4 and 1.1.x before 1.1.2 allows remote attackers to have an unspecified impact via a large (1) cbp0 or (2) cbpz chunk in Westwood Studios VQA Video file, which triggers an out-of-bounds write.
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.