Executive Summary

The CVE-2026-7034 vulnerability affects the Tenda FH1202 router, version 1.2.0.14(408). It is a stack-based buffer overflow in the HTTP daemon (httpd), specifically within the function formWrlExtraSet.

The vulnerability arises because the function reads a user-supplied parameter named "GO" and stores it in a variable without validating its length. This variable is then passed to another function that copies it into a fixed-size stack buffer using sprintf, which can overflow if the input is too large.

An attacker can exploit this by sending a specially crafted HTTP POST request to the /goform/WrlExtraSet endpoint with an excessively long "GO" parameter, causing a stack-based buffer overflow.

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Impact Analysis

Successful exploitation of this vulnerability may allow an attacker to cause a denial of service (DoS) or achieve remote code execution on the affected device.

This means an attacker could potentially crash the router or take control of it remotely, leading to disruption of network services or unauthorized access.

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Detection Guidance

This vulnerability can be detected by sending a specially crafted HTTP POST request to the /goform/WrlExtraSet endpoint of the Tenda FH1202 router, version 1.2.0.14(408). The request should include an excessively long "GO" parameter to test for a stack-based buffer overflow.

A practical detection command involves using curl to send a POST request with a large "GO" parameter value, for example:

• curl -X POST http://[router_ip]/goform/WrlExtraSet -d "GO=$(python3 -c 'print("a"*1000)')"

If the device crashes, becomes unresponsive, or exhibits abnormal behavior after this request, it indicates the presence of the vulnerability.

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Mitigation Strategies

Immediate mitigation steps include restricting access to the vulnerable endpoint /goform/WrlExtraSet by implementing network-level controls such as firewall rules to block unauthorized or external access.

Additionally, avoid exposing the router's management interface to untrusted networks and monitor for unusual POST requests targeting the "GO" parameter.

Since the vulnerability arises from lack of input validation, applying any available firmware updates or patches from the vendor that address this issue is strongly recommended once available.

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Compliance Impact

The provided information does not specify any direct impact of the CVE-2026-7034 vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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