CVE-2025-4114: Critical Buffer Overflow Vulnerability in Netgear JWNR2000v2 1.0.0.11’s check_language_file Function

Overview

A critical vulnerability – CVE-2025-4114 – has been identified in Netgear JWNR2000v2 1.0.0.11, affecting the function check_language_file. This vulnerability poses a severe risk to users, as it allows for a buffer overflow attack that could potentially compromise the system or lead to data leakage. Despite being alerted early about this disclosure, the vendor has yet to respond or provide a solution.
This vulnerability is particularly significant because of its impact on both individual users and organizations. Given that the attack can be launched remotely, this raises concerns about the potential for unauthorized access to sensitive information, disruption of services, and overall system compromise.

Vulnerability Summary

CVE ID: CVE-2025-4114
Severity: Critical (CVSS score 8.8)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: System compromise, potential data leakage.

Affected Products

Product | Affected Versions

Netgear JWNR2000v2 | 1.0.0.11

How the Exploit Works

The exploit works by manipulating the argument “host” in the check_language_file function. This manipulation causes a buffer overflow, which is a condition where an operation writes data beyond the boundaries of fixed-length buffers. These buffers are regions of physical memory storage used to temporarily store data while it is being moved. When the written data overflows the buffer’s boundary and overwrites adjacent memory locations, it can cause program crashes, incorrect operation, or a security breach.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited using an HTTP request:

POST /check_language_file HTTP/1.1
Host: vulnerable_host
Content-Type: application/json
{ "host": "A"*5000 }

In this conceptual example, we send a POST request to the check_language_file endpoint of the vulnerable host. The “host” field in the JSON body is filled with a string of 5000 ‘A’ characters. The long string is designed to overflow the buffer, causing unexpected behavior in the system.

Mitigation Guidance

Until the vendor releases a patch, it is recommended to use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as temporary mitigation. These systems can help detect and block malicious traffic aimed at exploiting this vulnerability. If possible, users should also consider upgrading to a different model or device not affected by this vulnerability. An update to this issue will be provided once the vendor responds or a patch has been released.