FFmpeg is vulnerable to denial of service (DoS) attacks or possibly other attacks. A malicious user can pass a malicious mp4 file to the system to cause a use-after-free memory error in the system and cause it to crash.
seclists.org/fulldisclosure/2015/Apr/31
www.debian.org/security/2015/dsa-3288
www.securityfocus.com/bid/74385
www.securitytracker.com/id/1032198
git.libav.org/?p=libav.git;a=blob;f=Changelog;hb=refs/tags/v11.4
github.com/FFmpeg/FFmpeg/commit/e8714f6f93d1a32f4e4655209960afcf4c185214
security.gentoo.org/glsa/201705-08