Stack-Based Buffer Overflow in Belkin F9K1015 Remote Password Set

Impact Analysis

This vulnerability can have serious impacts including:

• Denial of Service (DoS): An attacker can crash the router, causing network disruption.
• Remote Code Execution (RCE): An attacker can execute arbitrary code on the device remotely, potentially taking full control of the router.
• Compromise of network security: With control over the router, attackers can intercept, modify, or redirect network traffic.
• Potential further attacks on connected devices or networks due to compromised router.

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Compliance Impact

The provided information does not specify how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

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Executive Summary

CVE-2026-5614 is a critical security vulnerability in the Belkin F9K1015 router firmware version 1.00.10. It is a stack-based buffer overflow found in the web interface, specifically in the formSetPassword function. The vulnerability arises because the function copies a user-supplied parameter named "webpage" into a buffer without checking its length, using the unsafe strcpy function. This allows an attacker to send an excessively long "webpage" parameter in a POST request to the /goform/formSetPassword endpoint, causing the buffer to overflow.

Exploiting this vulnerability can lead to denial of service (DoS) or remote code execution (RCE) on the affected device, meaning an attacker could crash the device or run arbitrary code remotely.

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Detection Guidance

This vulnerability can be detected by sending a specially crafted POST request to the vulnerable endpoint /goform/formSetPassword with an excessively long "webpage" parameter. Monitoring network traffic for such suspicious POST requests targeting this endpoint may help identify exploitation attempts.

A practical detection method is to use a command-line tool like curl to send a test POST request with a large payload in the "webpage" parameter and observe the device's response or behavior.

• curl -X POST http://<device-ip>/goform/formSetPassword -d "webpage=$(python3 -c 'print("A"*1000)')"

If the device crashes, becomes unresponsive, or behaves abnormally 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 web interface endpoint /goform/formSetPassword by implementing network-level controls such as firewall rules or access control lists to limit access only to trusted hosts.

Additionally, monitoring for unusual POST requests to this endpoint and disabling remote management features if not required can reduce the attack surface.

Since the vendor has not responded with a patch, consider isolating the affected device from untrusted networks until a fix or firmware update is available.

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