Secunia Security Advisory – Ubuntu has issued an update for expat. This fixes multiple vulnerabilities, which can be exploited by malicious people to cause a DoS (Denial of Service).
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/85477/sa38231.txt
Source: https://packetstormsecurity.com/files/85477/Secunia-Security-Advisory-38231.html