I have sudo access, but I don't remember the sudo or root password; how do I change it from my limited account using sudo?
As DopeGhoti mentions,
sudo asks for your user password, not the root password.
If you have neither the root password nor the password of an account that has
sudo rights, your next best bet is to reboot the server into maintenance mode, or if that doesn't work right, boot with
init=/bin/sh as part of the kernel command line to change the root password.