Linksys WRT54G Wireless-G Broadband Router allows remote attackers to bypass access restrictions and conduct unauthorized operations via a UPnP request with a modified InternalClient parameter, which is not validated, as demonstrated by using AddPortMapping to forward arbitrary traffic.

The Web interface in Linksys WRT54G 2.02.7 and BEFSR41 version 3, with the firewall disabled, allows remote attackers to attempt to login to an administration web page, even when the configuration specifies that remote administration is disabled.