CVE-2026-51653 in TOTOLINK
Summary
by MITRE • 08/28/2026
Incorrect access control in the getStorageCfg function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to obtain storage feature 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 the TOTOLINK T6 router, specifically within firmware version 4.1.5cu.748_B20211015, represents a critical failure in access control mechanisms embedded within the device's web management interface. The flaw resides in the getStorageCfg function, which is exposed through the Common Gateway Interface script located at /cgi-bin/cstecgi.cgi. This endpoint serves as an intermediary between user requests and internal system configurations, yet it fails to enforce proper authentication checks before processing specific administrative queries. Consequently, any actor with network access to the router can interact with this interface without providing valid credentials, bypassing standard security protocols designed to restrict sensitive configuration data to authorized administrators only.
From a technical perspective, the core issue is an improper authorization check within the application logic handling POST requests directed at the cstecgi.cgi script. When an attacker sends a crafted HTTP POST request targeting the getStorageCfg function, the server processes the command and returns detailed information regarding the storage feature state of the device. This data typically includes details about connected USB drives, their file systems, mount points, and potentially other metadata related to attached peripherals. The absence of session validation or token verification allows this sensitive operational data to be retrieved by unauthenticated entities, turning a routine configuration query into an unauthorized information disclosure vector.
The impact of this vulnerability extends beyond simple curiosity-driven reconnaissance. By obtaining storage feature state information, attackers can map the internal architecture and peripheral connections of the target device. This intelligence is often used as a precursor for more severe attacks, such as attempting to exploit vulnerabilities in connected USB devices or manipulating file system operations if further access controls are also weak. In environments where these routers serve as gateways for sensitive data, leaking storage configuration details can aid adversaries in planning lateral movement or identifying potential targets for ransomware deployment by revealing available writable storage locations. This aligns with the Common Weakness Enumeration category CWE-284, which describes Improper Access Control, and maps to MITRE ATT&CK technique T1087, specifically Endpoint OS Discovery, as it allows an attacker to enumerate system configuration details without prior authentication.
Mitigation strategies for this vulnerability primarily involve immediate firmware updates provided by the manufacturer if a patched version is available, ensuring that access control checks are correctly implemented in subsequent releases. In cases where patching is not immediately feasible, network-level controls should be employed to restrict access to the router's management interface exclusively from trusted IP addresses or internal subnets. Additionally, disabling remote administration features and changing default credentials can reduce the attack surface, although these measures do not directly fix the underlying code flaw in the getStorageCfg function. Security administrators must remain vigilant for similar patterns of unauthenticated API endpoints across other IoT devices to prevent broader exploitation campaigns targeting weak access control implementations.