The administrative web interface of a Netgear C7800 Router running firmware version 6.01.07 (and possibly others) authenticates users via basic authentication, with an HTTP header containing a base64 value of the plaintext username and password. Because the web server also does not utilize transport security by default, this renders the administrative credentials vulnerable to eavesdropping by an adversary during every authenticated request made by a client to the router over a WLAN, or a LAN, should the adversary be able to perform a man-in-the-middle attack.
The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.