A critical stack-based buffer overflow vulnerability in Tenda W3 firmware version 1.0.0.3(2204) allows remote attackers to potentially achieve arbitrary code execution.

The vulnerability exists within the formexeCommand function of the /goform/exeCommand component. By sending a crafted POST request with an oversized cmdinput parameter, an authenticated attacker can trigger a stack-based buffer overflow, leading to memory corruption.

Successful exploitation of this flaw allows an attacker to compromise the integrity and availability of the affected Tenda W3 device. Because the vulnerability results in memory corruption, it may lead to persistent system crashes or provide a vector for arbitrary code execution, potentially granting the attacker control over the network device. With a CVSS score of 8.8, this vulnerability represents a significant risk to network security, as the device serves as a critical entry point or gateway for internal traffic.

Immediate Action: Since a specific patch version is not currently identified, users should restrict access to the web management interface of the Tenda W3 device to trusted IP addresses only and disable remote management features where possible.

Proactive Monitoring: Monitor device system logs and network traffic for unusual POST requests directed at the /goform/exeCommand endpoint, which may indicate attempted exploitation.

Compensating Controls: Implement a Web Application Firewall (WAF) or an Intrusion Prevention System (IPS) rule to inspect and block excessively long inputs sent to the cmdinput parameter.

Public Exploit Available: Yes, a proof-of-concept exploit is available via the researcher's GitHub repository.

Given the availability of a public proof-of-concept and the high severity of the memory corruption flaw, organizations using Tenda W3 devices must treat this as a priority. Administrators should immediately audit their network perimeter to ensure management interfaces are not exposed to the public internet and apply vendor updates as soon as they become available to permanently remediate the overflow condition.