Root Password Readable in Clear Text with Ubuntu
He patched it within hours today, and posted to osnews with a description of what happened.
He also posted a copy on the ubuntu forums page including details of what happened.
It affects clean installs of breezy, and dapper upgrades from a breezy install, but not hoary or a clean dapper.
hoary = 5.04
breezy = 5.10
dapper = not officially released yet