Executive Summary

[{'type': 'paragraph', 'content': "CVE-2026-4008 is a stack-based buffer overflow vulnerability found in the Tenda W3 router firmware version 1.0.0.3(2204). It occurs in the POST parameter handler for the endpoint /goform/wifiSSIDset, specifically involving the 'index' and 'GO' parameters."}, {'type': 'paragraph', 'content': 'The vulnerability arises because the router copies the value of these parameters into fixed-size buffers on the stack without proper bounds checking. If an attacker sends an excessively long value in either parameter, it causes a stack overflow, which can corrupt memory.'}, {'type': 'paragraph', 'content': 'This memory corruption can lead to a crash of the device or potentially allow an attacker to execute arbitrary code remotely without authentication.'}] [1, 3, 4, 5]

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Impact Analysis

This vulnerability can have severe impacts on the affected device and its users.

• An attacker can remotely exploit the flaw without any authentication.
• Successful exploitation can cause the router to crash, resulting in denial of service.
• More critically, it may allow an attacker to execute arbitrary code on the device, potentially taking full control over it.
• This compromises the confidentiality, integrity, and availability of the device and any network it manages.

Because the router is a network device, such compromise could lead to further attacks on connected systems or interception of network traffic.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring or testing the POST requests sent to the endpoint /goform/wifiSSIDset on the Tenda W3 router version 1.0.0.3(2204). Specifically, detection involves checking for unusually long or malformed values in the POST parameters "index" or "GO" which are known to trigger the stack-based buffer overflow.'}, {'type': 'paragraph', 'content': 'A practical detection method is to send controlled POST requests with large payloads in the "index" or "GO" parameters to see if the device crashes or behaves abnormally, indicating the presence of the vulnerability.'}, {'type': 'list_item', 'content': 'Use curl or similar tools to send a POST request with a large payload to the vulnerable endpoint, for example:'}, {'type': 'list_item', 'content': 'curl -X POST http://<router-ip>/goform/wifiSSIDset -d "index=$(python3 -c \'print("A"*1000)\')"'}, {'type': 'list_item', 'content': 'curl -X POST http://<router-ip>/goform/wifiSSIDset -d "GO=$(python3 -c \'print("A"*1000)\')"'}, {'type': 'paragraph', 'content': 'If the device crashes, reboots, or shows signs of instability after such requests, it indicates the vulnerability is present.'}] [1, 3, 4, 5]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'Immediate mitigation steps for this vulnerability are limited because no known patches or countermeasures have been documented.'}, {'type': 'paragraph', 'content': 'The recommended action is to replace the affected Tenda W3 router version 1.0.0.3(2204) with an alternative device that is not vulnerable.'}, {'type': 'paragraph', 'content': "Additionally, restricting access to the router's management interface from untrusted networks and monitoring for suspicious POST requests to /goform/wifiSSIDset can help reduce the risk of exploitation."}] [2]

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