CVE-2026-51714 in TOTOLINK
Summary
by MITRE • 08/31/2026
Incorrect access control in the setRoamingCfg function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to alter roaming behavior via sending a crafted POST request to /cgi-bin/cstecgi.cgi.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/31/2026
The vulnerability identified in the setRoamingCfg function of TOTOLINK T6 router firmware version 4.1.5cu.748_B20211015 represents a critical failure in access control mechanisms, specifically classified under CWE-284 Improper Access Control. This flaw permits unauthenticated attackers to manipulate the device's roaming configuration by transmitting specially crafted HTTP POST requests to the /cgi-bin/cstecgi.cgi endpoint. In typical router architectures, administrative functions such as modifying network settings should require valid authentication credentials and session tokens to ensure that only authorized users can alter system parameters. However, in this specific implementation, the server-side validation logic fails to verify the identity or privilege level of the requester before processing the configuration change request. This oversight allows any external actor with network connectivity to the router's management interface to execute administrative commands without prior authentication.
From a technical perspective, the exploitation vector relies on the direct invocation of the setRoamingCfg function through standard web protocols. The attacker constructs an HTTP POST message containing specific parameters that dictate how the device should handle roaming behaviors, such as switching between wireless bands or adjusting signal thresholds for connected clients. Because the application does not enforce strict access controls at this endpoint, it processes these inputs and updates the internal configuration database accordingly. This type of vulnerability is often associated with CWE-862 Missing Authorization, where the software performs a privileged action without verifying that the caller has been authorized to perform it. The lack of input validation combined with the absence of authentication checks creates a straightforward path for exploitation, requiring only basic knowledge of HTTP request structures and the specific API endpoints exposed by the device's web interface.
The operational impact of this vulnerability is significant, as roaming configuration directly influences how wireless clients connect to and maintain connectivity with the access point. By altering these settings maliciously, an attacker can degrade network performance, cause frequent disconnections for legitimate users, or force devices onto less secure bands if multiple SSIDs are configured. In more severe scenarios, improper roaming configurations could be leveraged as a precursor to further attacks, such as man-in-the-middle operations where the attacker manipulates client association behaviors to intercept traffic. Furthermore, since this function is accessible without authentication, it effectively bypasses any perimeter security measures that rely on user credentials for administrative access, rendering traditional password-based defenses ineffective against remote exploitation attempts over the local network or potentially via NAT traversal if port forwarding is misconfigured.
Mitigation strategies must focus on enforcing strict authentication and authorization checks at the application layer immediately upon receipt of requests to sensitive endpoints like /cgi-bin/cstecgi.cgi. The vendor should implement session validation middleware that ensures every administrative request originates from an authenticated user with appropriate privileges before executing any configuration changes. Additionally, implementing role-based access control can help restrict specific functions to administrators only. For users unable to update firmware immediately, network segmentation is recommended; placing the router's management interface on a separate VLAN or restricting access via firewall rules to trusted IP addresses can reduce the attack surface. Regularly updating to patched versions of the firmware that address these CWE-284 and CWE-862 deficiencies is essential for maintaining secure operations. Security monitoring tools should also be configured to detect anomalous POST requests targeting CGI endpoints, which may indicate active exploitation attempts aligned with techniques described in MITRE ATT&CK under privilege escalation or configuration manipulation tactics.