The Thomson/Alcatel SpeedTouch 7G router, as used for the BT Home Hub 6.2.6.B and earlier, allows remote attackers on an intranet to bypass authentication and gain administrative access via vectors including a '/' (slash) character at the end of the PATH_INFO to cgi/b, aka "double-slash auth bypass." NOTE: remote attackers outside the intranet can exploit this by leveraging a separate CSRF vulnerability. NOTE: SpeedTouch 780 might also be affected by some of these issues.
https://exchange.xforce.ibmcloud.com/vulnerabilities/41271
http://www.theregister.co.uk/2007/10/09/bt_home_hub_vuln/
http://www.securityfocus.com/archive/1/489009/100/0/threaded
http://www.securityfocus.com/archive/1/481835/100/0/threaded
http://www.gnucitizen.org/projects/router-hacking-challenge/
http://www.gnucitizen.org/blog/bt-home-flub-pwnin-the-bt-home-hub