If I understand correctly it is a vulnerability in the parsing of subtiltles by multiple mediaplayers. They name 4 but there could be more right? I hope I’m safe by using mpv and using srt subtitles.
edit: After watching the video it looks like it is the way those mediaplayers download the subtitle from opensubtitles.org that causes the vulnerability. And the vultnerability is that they can connect to your pc via vnc. So that will be mostly windows pc’s.