Overview
The cybersecurity landscape is constantly evolving with new threats continually emerging. One of these threats is a critical vulnerability identified as CVE-2025-5849. This vulnerability affects the popular Tenda AC15 15.03.05.19_multi router. The flaw lies in the function formSetSafeWanWebMan of the file /goform/SetRemoteWebCfg of the HTTP POST Request Handler.
This vulnerability matters because it can lead to a stack-based buffer overflow, potentially resulting in system compromise or data leakage. Since it’s possible to initiate the attack remotely and the exploit is already public, the risk for users is significant.
Vulnerability Summary
CVE ID: CVE-2025-5849
Severity: Critical (8.8 CVSS)
Attack Vector: Network
Privileges Required: None
User Interaction: None
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 AC15 | 15.03.05.19_multi
How the Exploit Works
This vulnerability stems from improper validation of user-supplied data, which can lead to a stack-based buffer overflow. The problem occurs when the remoteIp argument is manipulated in the HTTP POST Request Handler. This could allow an attacker to overwrite the allocated buffer, leading to the execution of arbitrary code, or even cause the system to crash, resulting in a denial of service.
Conceptual Example Code
Here’s a conceptual example of how this vulnerability might be exploited. This is a simple HTTP POST request with manipulated remoteIp argument:
POST /goform/SetRemoteWebCfg HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
remoteIp=192.168.1.1%00[insert malicious code here]In this example, the IP address has been followed by a null byte (%00), effectively terminating the string. The malicious code following the null byte could then overflow the buffer.
Mitigation
The best way to mitigate this vulnerability is by applying the patch provided by the vendor. If the patch can’t be applied immediately, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. It is also advisable to limit access to the vulnerable system to trusted networks and hosts.
Ultimately, staying updated with the latest security patches and maintaining a robust security infrastructure are key to minimizing the risk of such vulnerabilities.