CVE-2025-4346: Critical Buffer Overflow Vulnerability in D-Link DIR-600L

Overview

The Common Vulnerabilities and Exposures (CVE) system has recently identified a critical vulnerability (CVE-2025-4346) within D-Link DIR-600L routers up to version 2.07B01. This vulnerability pertains to a severe buffer overflow issue in the formSetWAN_Wizard534 function, posing serious risks to users of the affected products. This problem is particularly concerning due to the potential for remote exploitation and the fact that it affects products that are no longer supported by the maintainer, posing a serious risk to users who are unable to apply vendor patches.

Vulnerability Summary

CVE ID: CVE-2025-4346
Severity: Critical (CVSS: 8.8)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

D-Link DIR-600L | Up to 2.07B01

How the Exploit Works

The vulnerability arises from an improper handling of the ‘host’ argument within the formSetWAN_Wizard534 function. A malicious actor can manipulate this argument, causing a buffer overflow condition. This can result in unexpected behavior, including potential system compromise or data leakage. Since this exploit can be launched remotely, an attacker doesn’t need physical access to the device, further amplifying the risk factor associated with this vulnerability.

Conceptual Example Code

Here’s a conceptual example of how an attacker might exploit this vulnerability:

POST /formSetWAN_Wizard534 HTTP/1.1
Host: vulnerable-router.example.com
Content-Type: application/x-www-form-urlencoded
host=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

In the above example, an attacker sends an HTTP POST request to the formSetWAN_Wizard534 function with an excessively long ‘host’ argument, causing a buffer overflow.
Please note, this example is purely conceptual and provided for illustrative purposes only. Actual exploitation might be more complex and depend on various factors.

Recommended Mitigation Strategies

As the affected products are no longer supported by the vendor, a vendor patch may not be available. In such cases, users are advised to consider alternative mitigation strategies such as employing a Web Application Firewall (WAF) or an Intrusion Detection System (IDS). These can help in identifying and potentially blocking attack attempts. However, they only provide temporary mitigation and the best long-term solution would be to replace unsupported and vulnerable devices.