No internet access doesn't save you.
With file system access it can delete a file.
Without sudo access it can silently add something to your user's crontab so a few days from now it runs a custom shell script that does anything with internet access. If you're not checking into this sort of thing regularly, you wouldn't know.
It can add something to your user's shell's rc so when you open a new terminal session, a bad side effect happens.
Malware scanning won't protect from these sort of things and every time a new version is available, it's another opportunity for something bad to happen.
To be fair this isn't a problem unique to Obsidian. Code editor plugins and most programming language package managers have the same problem.
There is no sandboxing at all. Every plugin has full access to your computer.
Installing a plug-in and reviewing its code at that point is one thing. But if the plug-in can be updated withut you knowing, then there’s little guarantee of security.
I’m thinking maybe 1 or 2 weeks from now…
But almost all plugins would need to be rewritten?