The allocate_buffers function in libavcodec/alac.c in FFmpeg before 2.7.2 does not initialize certain context data, which allows remote attackers to cause a denial of service (segmentation violation) or possibly have unspecified other impact via crafted Apple Lossless Audio Codec (ALAC) data.
https://lists.debian.org/debian-lts-announce/2018/12/msg00010.html
http://www.securitytracker.com/id/1033483
http://git.videolan.org/?p=ffmpeg.git%3Ba=commit%3Bh=f7068bf277a37479aecde2832208d820682b35e6