Executive Summary

[{'type': 'paragraph', 'content': 'CVE-2026-2929 is a critical stack-based buffer overflow vulnerability found in the D-Link DWR-M960 wireless router, version 1.01.07. The flaw exists in the function sub_453140 within the file /boafrm/formWlAc, part of the Wireless Access Control Endpoint component.'}, {'type': 'paragraph', 'content': 'The vulnerability arises from improper handling of the "submit-url" argument. Specifically, when the "save_apply" parameter is present, the function uses an unsafe strcpy operation to copy the "submit-url" string into a fixed-size global buffer without verifying the length of the input. This lack of bounds checking allows a malicious actor to supply an oversized "submit-url" parameter, causing a stack-based buffer overflow.'}, {'type': 'paragraph', 'content': 'This overflow can lead to memory corruption, potentially allowing remote attackers to execute arbitrary code with root privileges or cause denial of service by crashing the web server or rebooting the device. The vulnerability can be exploited remotely without authentication, and a proof-of-concept exploit is publicly available.'}] [1, 2, 3]

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Impact Analysis

Exploitation of this vulnerability can have severe impacts on the affected device and network security.

• Denial of Service (DoS): The vulnerability can cause the web server (boa) to crash or the device to reboot, making the router unavailable.
• Arbitrary Code Execution: Attackers may overwrite function pointers or control structures, enabling execution of malicious code with root privileges on the device.
• Compromise of Confidentiality, Integrity, and Availability: The attacker can gain control over the device, potentially intercepting or manipulating network traffic.

Since the exploit can be performed remotely without authentication and public exploits exist, the risk to affected users is high.

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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 POST requests sent to the endpoint /boafrm/formWlAc on the D-Link DWR-M960 router, specifically those containing the parameters save_apply and an oversized submit-url value.'}, {'type': 'paragraph', 'content': 'A detection method involves capturing and analyzing network traffic for POST requests targeting /boafrm/formWlAc with unusually large submit-url parameters, which may indicate an attempted exploit.'}, {'type': 'paragraph', 'content': 'Suggested commands include using network packet capture tools such as tcpdump or Wireshark to filter HTTP POST requests to the vulnerable endpoint. For example:'}, {'type': 'list_item', 'content': "tcpdump -i <interface> -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'POST /boafrm/formWlAc'"}, {'type': 'list_item', 'content': 'Using curl or similar tools to test the endpoint by sending crafted POST requests with large submit-url parameters to observe if the device crashes or behaves abnormally.'}, {'type': 'paragraph', 'content': 'Additionally, monitoring device logs for crashes or reboots of the web server (boa) may help identify exploitation attempts.'}] [2, 3]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'There are no known mitigations or countermeasures available for this vulnerability.'}, {'type': 'paragraph', 'content': 'The recommended immediate step is to replace the affected D-Link DWR-M960 device with an alternative product that is not vulnerable.'}, {'type': 'paragraph', 'content': "Until replacement, it is advisable to restrict network access to the device's management interface to trusted users only, and monitor for suspicious activity targeting the vulnerable endpoint."}] [1]

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