CVE-2026-51641 in TOTOLINK
Summary
by MITRE • 08/28/2026
Incorrect access control in the getWiFiMeshConfig function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to obtain mesh configuration and runtime state information via sending a crafted POST request to /cgi-bin/cstecgi.cgi.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified in TOTOLINK T6 router firmware version 4.1.5cu.748_B20211015 represents a critical failure in access control mechanisms within the device's web management interface. Specifically, the flaw resides in the getWiFiMeshConfig function, which is exposed through the Common Gateway Interface script located at /cgi-bin/cstecgi.cgi. This architectural design allows unauthenticated users to interact with sensitive administrative functions without providing valid credentials or session tokens. The absence of proper authentication checks for this specific endpoint enables remote attackers to retrieve internal network configurations and runtime state data directly from the device, bypassing intended security boundaries that should restrict such access to authorized administrators only.
From a technical perspective, the exploitation vector involves sending a crafted POST request to the specified CGI script. Unlike typical administrative interfaces that require prior login authentication or session validation for sensitive operations, this particular function processes requests regardless of user identity. This oversight allows an attacker with network connectivity to the router's management interface to extract detailed mesh configuration parameters and current runtime states. The information obtained includes critical details about the wireless mesh topology, node relationships, signal strengths, channel assignments, and other operational metrics that define how the device manages its local area network connections.
The impact of this vulnerability extends beyond simple data leakage. By obtaining mesh configuration and runtime state information, an attacker gains significant insight into the network's architecture and current operational status. This intelligence can be leveraged for further malicious activities such as targeted denial-of-service attacks against specific nodes, manipulation of routing tables to facilitate man-in-the-middle attacks, or identification of weak security configurations that could be exploited in subsequent stages of an attack chain. The exposure of runtime state information is particularly dangerous as it reveals the real-time health and connectivity status of all devices within the mesh network, providing a comprehensive map for potential adversaries aiming to disrupt service integrity or perform lateral movement within the local network environment.
This vulnerability aligns with CWE-284 Improper Access Control, where insufficient restrictions are applied to actions performed by authenticated users or unauthenticated actors accessing sensitive resources. Additionally, it relates to CWE-200 Information Exposure, as the flaw results in the disclosure of information that could be detrimental to security posture. In terms of MITRE ATT&CK framework classification, this behavior corresponds to T1506 Post-exploitation activities involving gathering network configuration data and potentially T1498 Network Denial of Service if the extracted state is used to target specific nodes for disruption. The lack of authentication enforcement on administrative endpoints represents a fundamental deviation from secure coding practices recommended by industry standards such as OWASP Top 10, specifically under categories related to broken access control and security misconfiguration.
Mitigation strategies must focus on enforcing strict authentication requirements for all administrative functions within the CGI interface. Developers should implement session validation checks before processing any requests directed at sensitive endpoints like getWiFiMeshConfig. Additionally, implementing role-based access controls ensures that only users with appropriate privileges can execute configuration retrieval operations. Network-level mitigations include restricting access to the management interface via IP whitelisting or VLAN segmentation to limit exposure to untrusted networks. For end-users, applying the latest firmware updates provided by TOTOLINK is essential as these often contain patches for such vulnerabilities. Until patched, administrators should disable remote management features if not strictly necessary and monitor logs for unusual POST requests targeting the cstecgi.cgi script to detect potential exploitation attempts in real-time.