The decode_slice_header function in libavcodec/h264.c in FFmpeg before 1.1 allows remote attackers to have an unspecified impact via crafted H.264 data, which triggers an out-of-bounds array access.
http://www.ffmpeg.org/security.html
http://www.debian.org/security/2013/dsa-2793
http://git.videolan.org/?p=ffmpeg.git%3Ba=commitdiff%3Bh=d6c184880ee2e09fd68c0ae217173832cee5afc1