Yes, if you boot into recovery mode, you will get a root command prompt.
You can then add a new password from there, or even create a new
privileged user pretty quickly. Can't help you much on mobile as
autocorrect keep sending infuriating me by changing the commands. But the
relevant direction set you want from Google is likely to pop up with the
following searches:

Ubuntu 11.10 boot into recovery mode

And

Linux command line change user password

There are also ways to do this from live cd, but I am not familiar with
them. (I'm also assuming recovery mode still works it did several years
ago)