http://thehackernews.com/2012/04/more-than-100000-wireless-routers-have.html
More than 100000 Wireless Routers have Default Backdoor
Some 100,000 routers of type Speedport W921V, W504V and W723V are affected in Germany alone. What makes things worse is the fact that in order to exploit the backdoor, no button has to be pushed on the device itself and on some of the affected routers, the backdoor PIN ("12345670") is still working even after WPS has been disabled by the user. The only currently known remedy for those models is to disable Wi-Fi altogether. Since all Arcadyan routers share the same software platform, more models might be affected.