Ubuntu Security Notice 507-1 – It was discovered that the TCP wrapper library was incorrectly allowing connections to services that did not specify server-side connection details. Remote attackers could connect to services that had been configured to block such connections. This only affected Ubuntu Feisty.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/58956/USN-507-1.txt
Source: https://packetstormsecurity.com/files/58956/Ubuntu-Security-Notice-507-1.html