A stack-based buffer overflow vulnerability in Tenda i3 firmware version 1.0.0.6(2204) poses a critical risk of remote code execution for authenticated users.

This vulnerability is a stack-based buffer overflow located in the formexeCommand function of the /goform/exeCommand endpoint. The flaw is triggered by sending a maliciously crafted, oversized payload to the cmdinput parameter, which can be exploited by an authenticated attacker to corrupt memory and potentially execute arbitrary code on the device.

Successful exploitation of this vulnerability allows an attacker to achieve remote code execution on the affected hardware. This could lead to a complete compromise of the device, enabling the attacker to intercept network traffic, pivot into internal network segments, or permanently disable the device, resulting in significant operational downtime and security exposure. With a CVSS score of 8.8, this vulnerability represents a high-severity threat that requires immediate attention from network administrators.

Immediate Action: Since no official patch is currently available from the vendor, administrators should immediately restrict access to the web management interface of the Tenda i3 device to trusted internal management subnets only.

Proactive Monitoring: Monitor device logs for unusual POST requests directed at the /goform/exeCommand endpoint, particularly those containing excessively large data strings in the cmdinput parameter.

Compensating Controls: Implement a network-level Web Application Firewall or an Intrusion Prevention System (IPS) rule to inspect and block inbound HTTP requests that contain anomalous payloads directed at the vulnerable /goform/exeCommand path.

Public Exploit Available: Yes, a proof-of-concept exists as documented in the security researcher's technical write-up on GitHub.

Given the availability of a public proof-of-concept and the potential for remote code execution, this vulnerability poses a severe risk to network integrity. Organizations utilizing Tenda i3 devices must prioritize isolating these units from untrusted networks and monitor for unauthorized access attempts. Please maintain close contact with Tenda support channels to deploy the official firmware update as soon as it becomes available.