after some reading at http://www.seattlewireless.net/index.cgi/LinksysWrt54g
i can confirm that the wl500g is vulnerable too,
when you send only a GET command to the httpd server, the httpd seems to halt, and the router reboots
you can test it yourself very simple by doing this:
telnet my.router 80
type 'GET' and press enter
you'll see the screen closes itselves immediately and the router is rebooting at that time already
