Overview
Cybersecurity enthusiasts and professionals alike need to be aware of a recently discovered and publicly disclosed vulnerability, CVE-2025-8810, within the Tenda AC20 16.03.08.05. This vulnerability, classified as critical, affects the strcpy function of the file /goform/SetFirewallCfg through the manipulation of the argument firewallEn, leading to a stack-based buffer overflow. Given the critical nature of this exploit, it has the potential to compromise systems or leak sensitive data, creating a significant risk for organizations and individuals utilizing the affected product. The bug is particularly concerning as it can be launched remotely, thus amplifying its potential damage.
Vulnerability Summary
CVE ID: CVE-2025-8810
Severity: Critical (CVSS: 8.8)
Attack Vector: Remote
Privileges Required: None
User Interaction: Not required
Impact: Potential system compromise or data leakage
Affected Products
Escape the Surveillance Era
Most apps won’t tell you the truth.
They’re part of the problem.
Phone numbers. Emails. Profiles. Logs.
It’s all fuel for surveillance.
Ameeba Chat gives you a way out.
- • No phone number
- • No email
- • No personal info
- • Anonymous aliases
- • End-to-end encrypted
Chat without a trace.
Product | Affected Versions
Tenda AC20 | 16.03.08.05
How the Exploit Works
The exploit works by taking advantage of a stack-based buffer overflow vulnerability in the strcpy function of the /goform/SetFirewallCfg file in the Tenda AC20 router firmware. An attacker can maliciously manipulate the argument ‘firewallEn’ to overflow the buffer, which can potentially lead to arbitrary code execution. This means that the attacker can perform any operation on the system, leading to a complete system compromise or data leakage.
Conceptual Example Code
Here is a conceptual example of how the vulnerability might be exploited. This example assumes the attacker sends a malicious HTTP POST request to the vulnerable endpoint:
POST /goform/SetFirewallCfg HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
firewallEn=1&buffer=[Insert malicious payload here]In this example, ‘[Insert malicious payload here]’ would be replaced with a payload designed to overflow the buffer, potentially leading to arbitrary code execution.
Mitigation
To mitigate this vulnerability, it is recommended to apply the vendor patch as soon as it becomes available. In the meantime, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation strategy, helping to identify and block potential exploit attempts.