CVE-2026-51644 in TOTOLINK
Summary
by MITRE • 08/28/2026
Incorrect access control in the getCrpcConfig 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 getCrpcConfig function, which is invoked when processing requests directed to the /cgi-bin/cstecgi.cgi endpoint. This component is responsible for retrieving configuration data related to cloud remote-control features, including status indicators and Uniform Resource Locator (URL) information necessary for establishing connections with external management servers. The core technical deficiency lies in the absence of proper authentication checks or session validation before executing this function. Consequently, any entity capable of reaching the router's web interface over a network connection can trigger this code path without providing valid credentials. This lack of enforcement allows unauthenticated actors to extract sensitive operational data that should be restricted to authorized administrators only.
From an offensive security perspective, this vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-284, which describes Improper Access Control. The exploitation vector is classified under MITRE ATT&CK technique T1078, specifically Valid Accounts or Default Accounts if default credentials are used, but more accurately as an unauthenticated access flaw often categorized under reconnaissance activities where attackers gather information to plan further attacks. By obtaining the cloud remote-control status and associated URLs, an attacker gains insight into whether the device is actively managed via a cloud service and can identify the specific endpoints involved in that communication. This information facilitates subsequent phases of attack such as credential stuffing against those external services or crafting targeted phishing campaigns based on the identified infrastructure components.
The operational impact of this vulnerability extends beyond simple data leakage. The exposure of remote-control URLs may reveal internal network topology details if these addresses contain local IP ranges or specific domain structures tied to the manufacturer's private cloud infrastructure. Furthermore, knowledge that a device is configured for cloud management might encourage attackers to focus on compromising the associated user accounts rather than attempting direct exploitation of the router itself. If an attacker successfully compromises the linked cloud account using information gathered from this vulnerability, they could gain persistent remote access to the network through legitimate administrative channels, bypassing local security controls entirely. This transforms a simple information disclosure into a potential full system compromise scenario depending on the strength of associated authentication mechanisms elsewhere in the ecosystem.
Mitigation strategies for this issue primarily involve applying vendor-provided firmware updates that patch the getCrpcConfig function with appropriate access control checks. Until such patches are available, network administrators should restrict access to the router's management interface by implementing strict firewall rules that limit connectivity to trusted IP addresses only. Additionally, disabling cloud remote-control features if they are not strictly necessary reduces the attack surface and eliminates the utility of this specific vulnerability for attackers. Regular monitoring of administrative logs for unauthorized POST requests to /cgi-bin/cstecgi.cgi can also aid in early detection of exploitation attempts. Ensuring that default passwords have been changed is a secondary but essential step, although it does not fully mitigate this specific unauthenticated access flaw since the initial request bypasses authentication entirely.