An issue was discovered in Libav 12.3. A read access violation in the mov_probe function in libavformat/mov.c allows remote attackers to cause a denial of service (application crash), as demonstrated by avconv.
https://lists.debian.org/debian-lts-announce/2019/09/msg00000.html
https://docs.google.com/document/d/18xCwfxMSJiQ9ruQSVaO8-jlcobDjFiYXWOaw31V37xo/edit