Compliance Impact

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Executive Summary

[{'type': 'paragraph', 'content': 'CVE-2026-3768 is a critical stack-based buffer overflow vulnerability found in the Tenda F453 router, version 1.0.0.3. The flaw exists in the function formWrlExtraSet within the /goform/WrlExtraSet endpoint. It arises from improper handling of the user-supplied parameter "GO", which is copied into a stack-based buffer without length validation using the sprintf function. This lack of boundary checks allows an attacker to overflow the buffer by sending a crafted HTTP POST request with an excessively long "GO" parameter.'}, {'type': 'paragraph', 'content': 'This vulnerability can be remotely exploited without requiring local or physical access, potentially leading to denial of service (DoS) or remote code execution (RCE) on the affected device.'}] [1, 2, 3]

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Impact Analysis

Exploitation of this vulnerability can compromise the confidentiality, integrity, and availability of the affected Tenda F453 router. An attacker can remotely execute arbitrary code or cause a denial of service (DoS) by sending specially crafted requests to the vulnerable endpoint.

• Remote code execution (RCE) allowing full control over the device.
• Denial of service (DoS) causing the device to crash or become unresponsive.
• Potential compromise of network security due to control over the router.

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Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring for HTTP POST requests sent to the endpoint /goform/WrlExtraSet containing an unusually long or crafted "GO" parameter. Such requests may indicate attempts to exploit the stack-based buffer overflow.'}, {'type': 'paragraph', 'content': 'A practical detection method is to capture and analyze network traffic for POST requests targeting /goform/WrlExtraSet with large or suspicious payloads in the "GO" parameter.'}, {'type': 'list_item', 'content': 'Use a network packet capture tool like tcpdump or Wireshark to filter HTTP POST requests to /goform/WrlExtraSet.'}, {'type': 'list_item', 'content': "Example tcpdump command: tcpdump -i <interface> -A 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep -i 'POST /goform/WrlExtraSet'"}, {'type': 'list_item', 'content': 'Use curl or similar tools to test the endpoint by sending crafted POST requests with large "GO" parameter values to check for abnormal behavior or crashes.'}, {'type': 'list_item', 'content': 'Example curl command to test: curl -X POST http://<router-ip>/goform/WrlExtraSet -d \'GO=$(python3 -c "print(\'a\'*1000)")\''}] [1, 3]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'No known mitigations or countermeasures have been identified for this vulnerability.'}, {'type': 'paragraph', 'content': 'The recommended immediate step is to replace the affected Tenda F453 router (version 1.0.0.3) with an alternative product that is not vulnerable.'}, {'type': 'paragraph', 'content': "Additionally, restricting remote access to the device's management interface and monitoring for suspicious activity may help reduce exposure until replacement."}] [1]

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