CVE-2026-51647 in TOTOLINK
Summary
by MITRE • 08/28/2026
Incorrect access control in the getCrpcCfg function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to obtain cloud remote-control status and URL 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 getCrpcCfg function, which is invoked when processing requests directed to the /cgi-bin/cstecgi.cgi endpoint. This component is designed to handle configuration queries related to cloud remote-control features, yet it lacks proper authentication checks or authorization validation for sensitive data retrieval operations. As a result, any unauthenticated actor on the network can interact with this function without providing valid credentials, bypassing standard security controls intended to restrict administrative access.
From a technical perspective, the core issue is an improper implementation of access control logic within the CGI script handling cloud configuration requests. The getCrpcCfg function retrieves and returns sensitive operational parameters, including the current status of remote management capabilities and associated Uniform Resource Locator information used for connecting to cloud services. Because these endpoints are exposed without requiring prior authentication, attackers can send crafted POST requests directly to the vulnerable endpoint. This allows them to extract internal network configuration details that should remain confidential, effectively turning a routine administrative query into an unauthorized data exfiltration vector.
The operational impact of this vulnerability is significant for users relying on cloud-based remote management features. By obtaining the cloud remote-control status and URL information, attackers can determine whether the device has active remote access enabled and identify the specific endpoints used for such connections. This intelligence facilitates further attacks, including potential man-in-the-middle attempts against the cloud communication channel or targeted exploitation of other vulnerabilities in the remote control infrastructure. Additionally, exposure of internal configuration details aids reconnaissance efforts, allowing adversaries to map out network topology and plan more sophisticated intrusion campaigns with greater precision and reduced risk of detection during initial phases.
This vulnerability aligns closely with Common Weakness Enumeration category CWE-284, which describes Improper Access Control, as well as CWE-359 regarding Exposure of Private Information to an Unauthorized Actor. In the context of the MITRE ATT&CK framework for IoT devices and network infrastructure, this behavior corresponds to techniques involving Discovery through Network Service Scanning and potentially Data from Information Repositories if the cloud URLs reveal additional service dependencies. The lack of authentication on a sensitive configuration endpoint represents a fundamental deviation from secure coding practices recommended by industry standards such as OWASP Top 10 for Internet of Things devices.
Mitigation strategies must prioritize immediate patching to the latest firmware version released by TOTOLINK, which likely includes fixes for this access control deficiency. In environments where updating is not immediately feasible, network segmentation should be enforced to restrict access to the router's management interface exclusively from trusted internal subnets. Furthermore, administrators should disable cloud remote-control features if they are not actively required, thereby reducing the attack surface and eliminating the utility of the exposed endpoint for malicious actors. Regular audits of web application security controls and implementation of strict input validation alongside robust authentication checks on all CGI endpoints are essential preventive measures to mitigate similar risks in network infrastructure devices.