Secunia Security Advisory – Ubuntu has acknowledged a security issue in pam, which can be exploited by malicious, local users to gain escalated privileges.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/91625/sa40512.txt
Source: https://packetstormsecurity.com/files/91625/Secunia-Security-Advisory-40512.html