NETGEAR Nighthawk WiFi6 Router prior to V1.0.10.94 contains a file sharing mechanism that allows users with access to this feature to access arbitrary files on the device.
The default console presented to users over telnet (when enabled) is restricted to a subset of commands. Commands issued at this console, however, appear to be fed directly into a system call or other similar function. This allows any authenticated user to execute arbitrary commands on the device.
A support user exists on the device and appears to be a backdoor for Technical Support staff. The default password for this account is “support” and cannot be changed by a user via any normally accessible means.