The ff_frame_thread_init function in libavcodec/pthread_frame.c in FFmpeg before 2.7.2 mishandles certain memory-allocation failures, which allows remote attackers to cause a denial of service (invalid pointer access) or possibly have unspecified other impact via a crafted file, as demonstrated by an AVI file.
https://lists.debian.org/debian-lts-announce/2018/12/msg00009.html
http://www.securitytracker.com/id/1033483
http://git.videolan.org/?p=ffmpeg.git%3Ba=commit%3Bh=f1a38264f20382731cf2cc75fdd98f4c9a84a626