Replying to this before OP asks.

Usenet is distributed across hundreds (thousands maybe?) of servers. It’s centralized in that setting up your own server and getting the same access as joining an existing Usenet server is going to be very difficult (and with Usenet being used for privacy more and more, could be impossible due to admins not trusting a random new person), but in theory one could.

I’ll be the first to admit to not paying much attention to Linux vulnerabilities, but I agree, I feel like a vulnerability in a package like sudo would have been huge news.

Most ISPs (especially smaller ones it seems) just run a basic DHCP server with leases expiring at a set interval. As long as your stuff is on and working when the lease renews, you’ll pull the same IP forever.