A critical stack-based buffer overflow vulnerability in Tenda M3 firmware allows remote attackers to trigger memory corruption and potentially achieve arbitrary code execution.

This vulnerability is a stack-based buffer overflow (CWE-121) located in the formSetRemoteDhcpForAp function within the /goform/setDhcpAP endpoint. An authenticated attacker can trigger this flaw by sending a specially crafted POST request containing oversized parameters, such as startip, endip, leasetime, gateway, dns1, or dns2.

Successful exploitation of this vulnerability permits a remote attacker to corrupt memory and potentially execute arbitrary code on the affected router. This level of access could lead to a complete compromise of the network gateway, enabling unauthorized traffic interception, lateral movement within the local network, and persistent denial of service. Given the CVSS score of 8.8, this poses a severe risk to organizational infrastructure and data integrity.

Immediate Action: Contact Tenda support or check the official vendor portal for firmware updates addressing this buffer overflow, as no official patch version is currently identified.

Proactive Monitoring: Monitor network traffic for unusual POST requests directed at the /goform/setDhcpAP endpoint and investigate logs for anomalous device behavior or unexpected router reboots.

Compensating Controls: Implement a Web Application Firewall or network access control list to restrict access to the web management interface of the Tenda M3 to trusted administrative IP addresses only.

Public Exploit Available: Yes, a published proof-of-concept exists and is attributed to the researcher's write-up hosted on GitHub.

The severity of this vulnerability, combined with the availability of a public proof-of-concept, necessitates immediate attention. Security teams must restrict management interface access and maintain a high state of vigilance until an official firmware patch is provided by the vendor. Prioritize the isolation of affected devices from public-facing segments of the network to mitigate the risk of remote exploitation.