CVE-2019-9718 on Ubuntu 18.04 LTS (bionic) - medium.
Description:
In FFmpeg 4.1, a denial of service in the subtitle decoder allows attackers to hog the CPU via a crafted video file in Matroska format, because ff_htmlmarkup_to_ass in libavcodec/htmlsubtitles.c has a complex format argument to sscanf.