A critical stack-based buffer overflow vulnerability in Tenda M3 firmware (version 1.0.0.12) allows authenticated attackers to achieve remote code execution.

The vulnerability exists within the formQuickIndex function in the /goform/QuickIndex endpoint. An authenticated attacker can trigger a stack-based buffer overflow by sending a maliciously crafted payload to the PPPOEPassword parameter, which lacks sufficient length validation.

Successful exploitation of this vulnerability allows an attacker to execute arbitrary code on the affected network device, potentially leading to full system compromise or a denial of service. Given the CVSS score of 8.8, this flaw represents a significant risk to network integrity and availability. Unauthorized control over networking equipment can facilitate lateral movement within the environment, data interception, or the creation of persistent backdoors.

Immediate Action: Update the Tenda M3 firmware to the latest available version provided by the manufacturer. If a patch is not currently available, isolate the management interface of the device from untrusted networks.

Proactive Monitoring: Monitor network traffic for unusual POST requests directed at the /goform/QuickIndex endpoint. Review system logs for signs of service crashes or unauthorized configuration changes.

Compensating Controls: Implement strict access control lists on the network to limit management access to the device to known, trusted administrative workstations only.

Public Exploit Available: Yes, a functional proof of concept is available via the researcher's published technical documentation on GitHub.

This vulnerability presents a high risk due to the potential for remote code execution on core networking infrastructure. Administrators should prioritize firmware updates immediately to address this flaw. Where patching is delayed, restrict access to the device management interface to mitigate the risk of exploitation by authenticated attackers.