FFmpeg before 2.8.12, 3.0.x and 3.1.x before 3.1.9, 3.2.x before 3.2.6, and 3.3.x before 3.3.2 does not properly restrict HTTP Live Streaming filename extensions and demuxer names, which allows attackers to read arbitrary files via crafted playlist data.
https://lists.debian.org/debian-lts-announce/2019/01/msg00006.html
https://github.com/FFmpeg/FFmpeg/commit/a5d849b149ca67ced2d271dc84db0bc95a548abb
https://github.com/FFmpeg/FFmpeg/commit/189ff4219644532bdfa7bab28dfedaee4d6d4021