Ubuntu Security Notice 273-1: Yukihiro Matsumoto reported that Ruby’s HTTP module uses blocking sockets. By sending large amounts of data to a server application that uses this module, a remote attacker could exploit this to render this application unusable and not respond any more to other clients (Denial of Service).
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/45696/USN-273-1.txt
Source: https://packetstormsecurity.com/files/45696/Ubuntu-Security-Notice-273-1.html