Overview
A severe and critical vulnerability has been discovered in the TOTOLINK A702R 4.0.0-B20230721.1521, a widely used wireless network router. The flaw is not only dangerous due to its high severity score but also because it exposes an unknown part of the code to potential attackers, potentially leading to system compromise or data leakage. As TOTOLINK’s products are widely used in various industries, the scope of this vulnerability is broad, and it’s crucial to understand its implications and apply appropriate mitigation strategies.
Vulnerability Summary
CVE ID: CVE-2025-8140
Severity: Critical, CVSS score 8.8
Attack Vector: Remote, HTTP POST Request
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
TOTOLINK A702R | 4.0.0-B20230721.1521
How the Exploit Works
The vulnerability arises from an insecure handling of HTTP POST requests in the ‘submit-url’ argument of the file ‘/boafrm/formWlanMultipleAP.’ The improper validation and processing of this argument can lead to a buffer overflow condition. Buffer overflow is a classic vulnerability in which an application writes more data to a block of allocated memory (buffer) than it can hold, causing an overflow. This overflow can overwrite adjacent memory areas, potentially leading to arbitrary code execution, system crashes, and information disclosure.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited using a malformed HTTP POST request:
POST /boafrm/formWlanMultipleAP HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
submit-url=<malicious_payload>In the above pseudocode, `
Mitigation Guidance
The best way to mitigate this vulnerability is to apply the vendor-issued patch as soon as it becomes available. This patch will likely involve correcting the input validation for the ‘submit-url’ argument, preventing the possibility of buffer overflow.
In the meantime, users can implement a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as temporary mitigation. These systems can be configured to detect and block attempts to exploit this vulnerability. However, this should be considered a temporary solution and not a replacement for the vendor’s patch.