Overview
A critical vulnerability, CVE-2025-6393, has been discovered in several TOTOLINK networking products. These devices are commonly used in both home and professional settings to provide network connectivity. This makes the potential impact of this vulnerability severe, as successful exploitation could result in system compromise or data leakage. Cybersecurity professionals, network administrators, and individual users of these devices need to be aware of this threat and take appropriate measures to mitigate its risks.
Vulnerability Summary
CVE ID: CVE-2025-6393
Severity: Critical (CVSS 8.8)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: System compromise or data leakage
Affected Products
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Product | Affected Versions
TOTOLINK A702R | 3.0.0-B20230809.1615
TOTOLINK A3002R | 4.0.0-B20230531.1404
TOTOLINK A3002RU | 4.0.0-B20230721.1521
TOTOLINK EX1200T | 4.1.2cu.5232_B20210713
How the Exploit Works
The vulnerability lies in an unknown function of the file /boafrm/formIPv6Addr of the component HTTP POST Request Handler. By manipulating the “submit-url” argument, an attacker can cause a buffer overflow. This type of vulnerability occurs when more data is written into a block of memory, or buffer, than it can hold. In this case, the excess data overflows into adjacent memory, potentially overwriting other data or causing the system to crash. Remote attackers can exploit this vulnerability without requiring any user interaction or privileges.
Conceptual Example Code
Here is a conceptual example of how an HTTP POST request exploiting the vulnerability might look:
POST /boafrm/formIPv6Addr HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
submit-url=AAAAAAAAAAAA... // Long string of "A"s that causes buffer overflowIn the above example, the “submit-url” argument is filled with a long string of “A”s. This string is longer than what the buffer in the vulnerable function can handle, leading to a buffer overflow.
This example is purely conceptual and is provided to illustrate the nature of the exploit. It may not work in a real-world scenario, as actual exploitation would likely require a more complex payload and understanding of the system’s memory layout.
Mitigation
It is recommended that users of the affected products apply the vendor patch as soon as it becomes available. In the meantime, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. These systems can be configured to detect and block attempts to exploit this vulnerability, reducing the risk of successful attacks.