CVE-2026-51627 in TOTOLINK
Summary
by MITRE • 08/28/2026
Incorrect access control in the getIptvCfg function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to obtain IPTV and IGMP configuration 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 getIptvCfg function, which is exposed through the Common Gateway Interface script located at /cgi-bin/cstecgi.cgi. This architectural design allows external actors to interact with internal configuration modules without proper authentication checks or session validation. The core technical deficiency lies in the server-side logic that processes POST requests directed at this endpoint; it fails to verify whether the requesting entity possesses valid administrative credentials before executing the function and returning sensitive data. Consequently, any unauthenticated user on the network can exploit this misconfiguration by crafting a specific HTTP POST request to trigger the retrieval of internal settings.
From an operational perspective, the exploitation of this vulnerability results in the unauthorized disclosure of Internet Protocol Television (IPTV) and Internet Group Management Protocol (IGMP) configuration details. These configurations typically contain sensitive parameters such as VLAN IDs, multicast group addresses, authentication tokens for IPTV services, and network segmentation rules. The exposure of IGMP settings is particularly concerning because it reveals how the router handles multicast traffic routing, which can be leveraged by attackers to map internal network topology or potentially disrupt service availability through spoofed membership reports. Furthermore, access to IPTV configuration may expose credentials used for external streaming services or proprietary protocols, facilitating further lateral movement within a home or small business network environment where such routers are commonly deployed as the primary gateway device.
This vulnerability aligns with CWE-284, which classifies Improper Access Control, specifically highlighting failures in authorization checks that allow unauthorized data access. In terms of offensive security frameworks, this exploitation technique maps to MITRE ATT&CK tactic T1506, Post-exploitation: Collect Network Configuration Data, as the attacker gathers information about network services and configurations from a compromised or accessible device. The ability to retrieve these settings without authentication also touches upon CWE-200, Information Exposure, where sensitive system data is made available to unauthorized parties due to insufficient security controls in web application logic.
Mitigation strategies for this vulnerability primarily involve immediate firmware updates provided by the vendor if available, as patching typically involves adding strict access control checks and session validation tokens to the getIptvCfg function handler. In environments where updating is not immediately feasible, network segmentation should be implemented to restrict access to the router's management interface from untrusted networks or public-facing interfaces. Additionally, disabling unused services such as remote web administration can reduce the attack surface by ensuring that the vulnerable endpoint is only accessible via local area network connections behind a firewall. Security administrators should also monitor for unusual POST traffic patterns directed at /cgi-bin/cstecgi.cgi to detect potential exploitation attempts in real-time.