Impact Analysis

Exploitation of this vulnerability can lead to serious impacts including denial of service (DoS), where the affected device may crash or become unresponsive.

More critically, it may allow an attacker to execute arbitrary code remotely on the affected Tenda F451 device, potentially taking full control over it.

This could compromise the security and functionality of your network, leading to unauthorized access, data interception, or further attacks within your network environment.

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Executive Summary

CVE-2026-6120 is a stack-based buffer overflow vulnerability found in the Tenda F451 router firmware version 1.0.0.7. It occurs in the fromDhcpListClient function of the httpd service, specifically when processing the "page" parameter in an HTTP POST request to the /goform/DhcpListClient endpoint.

The vulnerability arises because the "page" parameter is passed directly to the sprintf function without any bounds checking, allowing an attacker to overflow the buffer by sending an excessively long string.

This can be exploited remotely by sending a specially crafted HTTP POST request with a very long "page" parameter, potentially causing a denial of service or enabling arbitrary remote code execution on the device.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious HTTP POST requests sent to the endpoint "/goform/DhcpListClient" that contain an excessively long "page" parameter.

A detection method involves capturing network traffic and inspecting POST requests to this endpoint for unusually large payloads in the "page" parameter, which may indicate an attempt to exploit the stack-based buffer overflow.

For example, using command-line tools like curl or wget, you can simulate or detect such requests.

• Use a network packet capture tool such as tcpdump or Wireshark to filter HTTP POST requests to "/goform/DhcpListClient".
• Example tcpdump command to capture relevant traffic: tcpdump -i <interface> -A 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep '/goform/DhcpListClient'
• Use curl to test the endpoint with a long "page" parameter to verify if the system is vulnerable: curl -X POST http://<target-ip>/goform/DhcpListClient -d 'page=$(python3 -c "print('a'*2048)")'

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Mitigation Strategies

Immediate mitigation steps include restricting access to the vulnerable endpoint "/goform/DhcpListClient" to trusted networks only, such as by using firewall rules or access control lists.

Additionally, monitoring and blocking HTTP POST requests with unusually large "page" parameters can help prevent exploitation.

If possible, update the firmware of the Tenda F451 device to a version that patches this vulnerability, which can be obtained from Tenda's official site.

Until a patch is applied, consider disabling the httpd service or the vulnerable functionality if feasible.

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Compliance Impact

The provided information does not specify how the vulnerability in Tenda F451 1.0.0.7 impacts compliance with common standards and regulations such as GDPR or HIPAA.

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