In NETGEAR Nighthawk X10-R900 prior to 1.0.4.24, an attacker may execute stored XSS attacks against this device by supplying a malicious X-Forwarded-For header while performing an incorrect login attempt. The value supplied by this header will be inserted into administrative logs, found at Advanced settings->Administration->Logs, and may trigger when the page is viewed. Although this value is inserted into a textarea tag, the attack simply needs to supply a closing textarea tag.