The ljpeg_decode_yuv_scan function in libavcodec/mjpegdec.c in FFmpeg before 2.8.2 omits certain width and height checks, which allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via crafted MJPEG data.
https://lists.debian.org/debian-lts-announce/2018/12/msg00009.html
http://lists.opensuse.org/opensuse-updates/2015-11/msg00146.html
http://git.videolan.org/?p=ffmpeg.git%3Ba=commit%3Bh=d24888ef19ba38b787b11d1ee091a3d94920c76a