Overview
This blog post is centered around a critical vulnerability identified as CVE-2025-7506. The vulnerability affects Tenda FH451 1.0.0.9, a popular networking product used by many organizations. This vulnerability, found within the HTTP POST Request Handler component, is of critical nature due to the potential consequences of its exploitation. The impact of a successful exploit can lead to system compromise, data leakage, and other potential broad-scale damages. As such, it is of paramount importance that organizations and individuals utilizing affected versions of this product take immediate steps to secure their systems.
Vulnerability Summary
CVE ID: CVE-2025-7506
Severity: Critical, CVSS Score 8.8
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
Tenda FH451 | 1.0.0.9
How the Exploit Works
The vulnerability resides in the fromNatlimit function of the /goform/Natlimit file. Attackers can manipulate the ‘page’ argument to trigger a stack-based buffer overflow. This overflow can then be leveraged to execute arbitrary code, potentially leading to full system compromise. The attack can be initiated remotely without any user interaction, making it especially dangerous.
Conceptual Example Code
Below is a conceptual example of how the vulnerability could be exploited. This is represented in the form of a malicious HTTP POST request.
POST /goform/Natlimit HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
page=AAAAA... {long string of "A" characters intended to overflow the buffer}This HTTP POST request exploits the vulnerability by sending an extremely long string of “A” characters as the ‘page’ argument. This causes the buffer to overflow, allowing the attacker to execute arbitrary code.
Mitigation Guidance
To mitigate this vulnerability, it is recommended to apply the vendor-supplied patch as soon as possible. If the patch cannot be applied immediately, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation strategy. These tools can help detect and block attempts to exploit this vulnerability, adding an extra layer of security to the affected systems.