web_shell_cmd.gch on ZTE F460 and F660 cable modems allows remote attackers to obtain administrative access via sendcmd requests, as demonstrated by using "set TelnetCfg" commands to enable a TELNET service with specified credentials.
https://github.com/injectionmethod/Windows-ZTE-Loader
https://github.com/injectionmethod/ZTE-Vuln-4-Skids