Heap-based buffer overflow in the vqa_decode_chunk function in the VQA codec (vqavideo.c) in libavcodec in Libav 0.5.x before 0.5.9, 0.6.x before 0.6.6, 0.7.x before 0.7.6, and 0.8.x before 0.8.2 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted VQA media file in which the image size is not a multiple of the block size.