Unpatched TOTOLINK AX1800 Router Flaw Allows Unauthenticated Telnet & Root RCE

A critical vulnerability has been uncovered in the TOTOLINK AX1800 wireless router, with CERT Coordination Center (CERT/CC) noting that there is currently no official patch. The flaw allows remote attackers to bypass authentication and gain full administrative control via a single HTTP request, by exploiting how the device handles requests to the /cgi-bin/cstecgi.cgi?action=telnet endpoint.

According to CERT Coordination Center (CERT/CC), an unauthenticated HTTP request can enable Telnet which may lead to remote code execution with root-level privileges. Once Telnet is active, attackers can log in and execute commands with root privileges, potentially altering DNS routing, intercepting traffic, and enabling lateral movement across the local network.

The advisory emphasises that a firmware update is necessary for complete remediation, and CERT/CC urges administrators to block WAN access, isolate the device, and monitor for unexpected Telnet activity on port 23 while a fix is awaited. The vulnerability is tracked as CVE-2025-13184 and highlights the risks of exposed web management interfaces for home and small business networks.