The JavaScript vector is a reasonable extrapolation based on how similar attacks like Meltdown, Spectre, or Heartbleed, eventually got their JavaScript exploits. There may not be one yet, but there’s likely to be one at some point.

It is still up in the air whether regular people with home computers need to be panicking.

That one’s easy: no, they don’t.

Even if an attacker were to get the disk encryption key from a regular user through some malicious JavaScript, the chances of them being able to actually exploit it, are slim to none. They’d still need some extra way to use that key, which would require a separate exploit, or physical access.

If it were a company computer, or the user got personally targeted (espionage, trade secrets, law enforcement, etc.)… then maybe worry a bit.

Hosting providers with shared servers, need to panic a lot. Anyone running a public server, be it at a provider or at home, should also panic a bit.