A critical stack-based buffer overflow vulnerability in Tenda F456 routers may allow remote attackers to achieve arbitrary code execution or cause a denial of service.

The vulnerability exists in the fromDhcpListClient function within the httpd component. An attacker can supply a crafted input to the page parameter, which is passed to the sprintf function without length validation, leading to a stack-based buffer overflow. While the CVSS vector indicates low privilege requirements, the flaw is remotely exploitable.

Successful exploitation of this vulnerability poses a severe risk to organizational infrastructure, as it enables remote code execution on the affected networking device. This could lead to full system compromise, unauthorized access to network traffic, and potential lateral movement into internal systems. With a CVSS score of 8.8, this vulnerability is classified as High and requires immediate attention to prevent device hijacking or service disruption.

Immediate Action: Since a specific patch version is currently unknown, administrators should restrict access to the device management interface to trusted internal networks only. If not already performed, disable remote management features on the device.

Proactive Monitoring: Monitor network traffic for suspicious POST requests directed at the /goform/DhcpListClient endpoint. Review system logs for unexpected crashes of the httpd service or unauthorized configuration changes.

Compensating Controls: Deploy a Web Application Firewall or an Intrusion Prevention System (IPS) rule to inspect and block excessively long payloads sent to the /goform/DhcpListClient URI.

Public Exploit Available: Yes, a published proof-of-concept exists as documented in the technical write-up provided by the researcher.

Due to the severity of this remote code execution flaw and the public availability of technical details, immediate mitigation is required. Administrators should prioritize restricting management access to the affected Tenda F456 units and monitor vendor channels closely for the release of a firmware update addressing the buffer overflow.