Overview
A critical vulnerability, identified as CVE-2025-7837, has recently been discovered in TOTOLINK T6 version 4.1.5cu.748_B20211015. This cybersecurity flaw has been classified as a severe threat due to its potential to compromise systems and leak sensitive data. In a world where digital security is paramount, such vulnerabilities can have serious implications on both a personal and organizational level, making this a matter of high importance.
The vulnerability affects the function recvSlaveStaInfo within the MQTT Service component of the TOTOLINK T6. The manipulation of the argument ‘dest’ can lead to buffer overflow, which could potentially be exploited by attackers to gain unauthorized access, disrupt services, or pilfer confidential data.
Vulnerability Summary
CVE ID: CVE-2025-7837
Severity: Critical (8.8 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential 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 vulnerability arises from an issue in the recvSlaveStaInfo function of the MQTT Service component of the TOTOLINK T6. Specifically, the manipulation of the ‘dest’ argument can cause a buffer overflow. Buffer overflows occur when a program writes more data to a fixed-length block of memory, or buffer, than it can hold. The extra data overwrites adjacent memory locations, potentially leading to erratic program behavior, crashes, or even the execution of malicious code.
The exploit can be launched remotely over a network without any requirement for user interaction or privileges, making it a significant threat to unpatched systems.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited using a specially crafted MQTT message:
POST /mqtt/recvSlaveStaInfo HTTP/1.1
Host: affected-device-ip
Content-Type: application/json
{
"dest": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA..."
}In the above example, the “dest” field is filled with an excessively long string, causing a buffer overflow in the handling program. Please note that the actual exploit will likely involve much more complex programming techniques and this example is provided only for conceptual understanding.
Mitigation Guidance
Users are advised to apply the vendor patch as soon as it becomes available. In the interim, employing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. These systems can help detect and prevent attempts to exploit this vulnerability.