LBT T300- T390 v2.2.1.8 were discovered to contain a stack overflow via the vpn_client_ip parameter in the config_vpn_pptp function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted POST request.
https://github.com/cvdyfbwa/IoT_LBT_Router/blob/main/config_vpn_pptp.md