One example I can think of is the WoW private server Warmane uses an RCE to extend client functionality.

https://www.reddit.com/r/wowservers/comments/1eebxwf/warning...

You've never needed to get root access on an old computer when nobody knows the password?

it doesnt have to be secret. for example unlocking old phones. There are certainly people waiting for the right exploits to get access to their old wallet.