Ubuntu, Kubuntu, Edubuntu, and Xubuntu PAM vulnerability could lead to remote, unauthorized access

http://seclists.org/fulldisclosure/2009/Sep/0046.html

A non-default configuration of Pam under Ubuntu 8.10 and Ubuntu 9.04
could lead to successful authentication of unauthorized users to an
Ubuntu machine.

"The problem can be corrected by upgrading your system to the following
package versions:

Ubuntu 8.10:

libpam-runtime 1.0.1-4ubuntu5.6

Ubuntu 9.04:

libpam-runtime 1.0.1-9ubuntu1.1"