The ff_mjpeg_decode_sof function in libavcodec/mjpegdec.c in FFmpeg before 2.5.4 does not validate the number of components in a JPEG-LS Start Of Frame segment, which allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via crafted Motion JPEG data.
https://lists.debian.org/debian-lts-announce/2019/03/msg00041.html
http://www.ubuntu.com/usn/USN-2944-1
http://www.securitytracker.com/id/1033078
http://www.securityfocus.com/bid/72644
http://git.videolan.org/?p=ffmpeg.git%3Ba=commit%3Bh=fabbfaa095660982cc0bc63242c459561fa37037