Executive Summary

CVE-2026-3978 is a critical stack-based buffer overflow vulnerability found in the D-Link DIR-513 router, version 1.10. It exists in an unknown function within the file /goform/formEasySetupWizard3 and is triggered by manipulating the argument wan_connected with crafted input.

This flaw allows an attacker to overwrite the local stack buffer, potentially compromising the confidentiality, integrity, and availability of the device.

The vulnerability can be exploited remotely without authentication, making it highly dangerous and easy to exploit.

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Impact Analysis

Exploiting this vulnerability can allow an attacker to perform a denial of service (DoS) attack or achieve remote code execution on the affected device.

This means the attacker can disrupt the normal operation of the router or take control of it remotely, potentially leading to loss of network availability, unauthorized access, and compromise of network security.

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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 for suspicious HTTP requests sent to the endpoint /goform/formEasySetupWizard3 on D-Link DIR-513 routers running firmware version 1.10. Specifically, crafted requests manipulating the wan_connected argument may indicate exploitation attempts.'}, {'type': 'paragraph', 'content': 'Network detection can involve capturing and inspecting HTTP traffic for POST or GET requests targeting /goform/formEasySetupWizard3 with unusual or malformed parameters.'}, {'type': 'paragraph', 'content': 'Example commands to detect such activity might include using network packet capture tools like tcpdump or tshark to filter HTTP requests to the vulnerable endpoint:'}, {'type': 'list_item', 'content': "tcpdump -i <interface> -A -s 0 'tcp port 80 and (((ip dst <router_ip>) and (tcp[((tcp[12:1] & 0xf0) >> 2):4] = 0x47455420)) or ((ip dst <router_ip>) and (tcp[((tcp[12:1] & 0xf0) >> 2):4] = 0x504f5354)))'"}, {'type': 'list_item', 'content': 'tshark -i <interface> -Y \'http.request.uri contains "/goform/formEasySetupWizard3"\' -T fields -e http.request.method -e http.request.uri -e http.file_data'}, {'type': 'paragraph', 'content': 'Additionally, reviewing router logs for unusual access patterns or malformed requests to this endpoint may help detect exploitation attempts.'}] [1, 2]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'There are no known countermeasures or mitigations available for this vulnerability in the affected D-Link DIR-513 firmware version 1.10.'}, {'type': 'paragraph', 'content': 'The recommended immediate step is to replace the affected device with an alternative product that is not vulnerable.'}, {'type': 'paragraph', 'content': "Until replacement, it is advisable to restrict network access to the router's management interface, especially blocking remote access to the /goform/formEasySetupWizard3 endpoint, to reduce the risk of exploitation."}] [1]

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