CVE-2026-51628 in TOTOLINK
Summary
by MITRE • 08/28/2026
Incorrect access control in the getGenerateWiFiWpsPin function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to generate and retrieve a new WPS PIN 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 getGenerateWiFiWpsPin function, which is exposed through the Common Gateway Interface (CGI) endpoint located at /cgi-bin/cstecgi.cgi. This architectural design allows external actors to interact with internal router functions without requiring prior authentication or valid session tokens. The absence of proper authorization checks means that any network user who can reach the administrative interface, whether from a local area network segment or potentially over the internet if port forwarding is misconfigured, can invoke this function directly via HTTP POST requests.
From a technical perspective, the core issue is an improper implementation of access control logic within the CGI handler. The getGenerateWiFiWpsPin endpoint was designed to assist legitimate administrators in retrieving or generating Wireless Protected Setup (WPS) PINs for device pairing purposes. However, the developers failed to implement sufficient validation steps to verify that the requesting entity possesses administrative privileges. Consequently, an unauthenticated attacker can craft a specific POST request containing parameters required by the function and send it to the designated CGI URL. The router processes this request as if it originated from an authenticated administrator session, thereby bypassing security boundaries intended to protect sensitive configuration data.
The operational impact of this vulnerability is significant due to the nature of WPS PINs in wireless network security. A generated or retrieved WPS PIN serves as a secondary authentication method for connecting devices to a Wi-Fi network without entering the primary password. If an attacker can obtain this PIN, they may exploit weaknesses inherent in the WPS protocol itself, such as brute-force attacks against the eight-digit PIN structure which has limited entropy. Furthermore, possessing valid credentials or PINs allows the attacker to join the protected wireless network, leading to potential eavesdropping on unencrypted traffic, man-in-the-middle attacks within the local segment, and lateral movement toward other internal assets. This effectively neutralizes the perimeter security provided by Wi-Fi encryption for connected clients.
This vulnerability aligns with CWE-284, which classifies Improper Access Control, as it involves a failure to restrict access to resources or functions based on user identity or privileges. In terms of offensive cybersecurity frameworks, this behavior maps closely to MITRE ATT&CK technique T1078, specifically Valid Accounts, where adversaries leverage legitimate credentials or authentication mechanisms that have been compromised or bypassed. The exploitation vector is classified as Network-based with Low Complexity, indicating that it requires minimal skill and specific network connectivity but no prior access.
Mitigation strategies for this vulnerability primarily involve immediate firmware updates provided by the vendor to patch the CGI handler's authorization logic. Until an official patch is available, administrators should disable remote management features if not strictly necessary, ensuring the administrative interface is only accessible from trusted internal networks behind a robust firewall. Additionally, disabling WPS functionality entirely in the wireless settings can mitigate the risk associated with PIN-based authentication methods, as it removes the attack surface exploited by this specific flaw. Regular auditing of router configurations and monitoring for unusual outbound traffic or unauthorized device associations on the network are also recommended defensive measures to detect potential exploitation attempts early.