PSOProxy is a "web server application designed to work with the Gamecube web browser. Its main purpose is to allow Phantasy Star Online snapshot files to be copied to a PC and converted to a common image file format". The server contains a vulnerability rendering it unable to process a large buffer provided inside the URL. The vulnerability can be exploited to cause the server to execute arbitrary code.
Credit:
The information has been provided by Donato Ferrante.