By opening http://192.168.0.1/setup.cgi?todo=debug you enable the router's debug mode.Then you just telnet at 192.168.0.1 at port 23 and then you have a root shell.

Also i found that if you just telnet to 192.168.0.1 2602 you will get a prompt from the service ZEBRA that is running on the router.By giving "zebra" as password *which is the default password* you got also a root shell.