Say there’s some exploit that allows some component of KDE to be used to read a file. If it’s running under an unprivileged user - it sucks. Everything in user’s homedir becomes fair game. But if it runs as root - it’s simply game over. Everything on the system is accessible. All config, all bad config, files of all applications (databases come to mind). Everything.
This is also something I’m thinking about: All the hard drives mounted on the server is accessible to the only regular user as that is what my other computers use to access them. I’m the only one with access to the server so everything is accessible under one user. The data on those drives is what I want to protect, so wouldn’t a vulnerability in either KDE or Firefox be just as dangerous to those files even running as the regular user?
Also, since my PC has those drives mounted through the server and accessible to the regular user that I use my PC as, wouldn’t a vulnerability in a program running as the regular user of my PC also compromise those files even if the server only hosted the files and did absolutely nothing else? Going back to the Firefox thing, if I had a sandbox breach on my PC, it would still be able to read the files on the server right? Wouldn’t that be just as bad as if I had been running Firefox as root on the server itself? Really feels like the only way to 100% keep those files safe is to never access them from an internet accessible computer, and everything else just falls short and is just as bad as the worst case scenario, though maybe I’m missing something. Am I just being paranoid about the non-root scenarios?