Overview
The cybersecurity industry has recently witnessed another critical vulnerability, CVE-2025-8170, that poses significant risk to TOTOLINK T6 routers. This vulnerability affects the ‘tcpcheck_net’ function of the file ‘/router/meshSlaveDlfw’ in the MQTT Packet Handler component. With the potential to compromise systems or lead to data leakage, this vulnerability has been classified as critical. It is noteworthy that this flaw can be exploited remotely, and thus, it requires immediate attention from network administrators and security teams managing TOTOLINK T6 routers.
Vulnerability Summary
CVE ID: CVE-2025-8170
Severity: Critical (8.8 CVSS Severity Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise or data leakage
Affected Products
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Product | Affected Versions
TOTOLINK T6 | 4.1.5cu.748_B20211015
How the Exploit Works
The exploit revolves around the manipulation of the ‘serverIp’ argument in the ‘tcpcheck_net’ function. The ‘serverIp’ argument is not properly validated, which allows a remote attacker to send a specially crafted MQTT packet causing a buffer overflow condition. This can lead to arbitrary code execution, potentially allowing the attacker to take control of the system or cause data leakage.
Conceptual Example Code
The vulnerability might be exploited with a malicious MQTT packet. Here is a conceptual representation of such an exploit:
POST /router/meshSlaveDlfw HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "serverIp": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA..." }In this conceptual example, “AAAAAAAA…” represents an overly long string that causes a buffer overflow. This is a simplified representation for illustrative purposes, and a real exploit would likely use more complex data to achieve code execution.
Mitigation Guidance
Users of TOTOLINK T6 routers are advised to apply the vendor patch as soon as it is available. Until then, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation. Regularly monitoring network traffic for any signs of abnormal activity can also help in early detection and prevention of an exploit.
Please note that this is a high-severity vulnerability. Prompt action is required to protect your systems and data from potential breaches.
