ZTE Modem Exploit?

Just got to know these ZTE ZXDSL crappy modems are full of vulnerabilities that can be easily exploited, you can access administrative functionality, e.g;

http://your-ip/adminpasswd.cgi (you can set a new username/password here)

http://your-ip/vpivci.cgi (access to configuration of modem, can even disclose PPPOE User & Password)

wth :S

404 not found here

ZXDSL 831DV2.1_A07

One thing I have been wondering for quite sometime. If someone hacks into your modem or router what can the do to exploit it melaciously. In my opinion there can be only static routing setup to your own PC and then you can do the MITM stuff or is there something more which i don't know.

Anyone got any idea???