Secunia Security Advisory – Ubuntu has issued an update for libx11. This fixes a vulnerability, which can be exploited by malicious, local users to disclose sensitive information or cause a DoS (Denial of Service).
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/56079/sa24953.txt
Source: https://packetstormsecurity.com/files/56079/Secunia-Security-Advisory-24953.html