No clue about the context but ironically the abbreviation is “If You Know, You Know”.

I manage multi user systems and try to be on top of this and no, privilege escalation with a working public exploit are very rare. There’s quite a lot of CVEs with potential privilege excalation, but most of the time there is no real world exploit. And a large part of those are related to user namespaces in one way or another.

This one is truly scary, at least the immediate mitigation is pretty straightforward.