A vulnerability in the TP-Link Archer c20 router with firmware version V6.6_230412 and earlier permits unauthorized individuals to bypass the authentication of some interfaces under the /cgi directory. When adding Referer: http://tplinkwifi.net to the the request, it will be recognized as passing the authentication. NOTE: this is disputed by the Supplier because the response to the API call is only "non-sensitive UI initialization variables."