Secunia Security Advisory – Ubuntu has issued an update for gnutls. This fixes some vulnerabilities, which potentially 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/43948/sa18918.txt
Source: https://packetstormsecurity.com/files/43948/Secunia-Security-Advisory-18918.html