A critical stack-based buffer overflow in the Tenda RX3 router, version 16.03.13.11, permits remote code execution, necessitating immediate attention to prevent unauthorized system control.

This vulnerability is a stack-based buffer overflow (CWE-121) caused by improper memory management within the /goform/fast_setting_wifi_set function. An authenticated attacker can trigger this memory corruption by supplying a specially crafted payload to the ssid_5g parameter.

Successful exploitation of this vulnerability allows an attacker to execute arbitrary code on the affected router. This level of access could lead to a complete compromise of the local network, facilitate man-in-the-middle attacks, or result in long-term persistence within the infrastructure. Given the CVSS score of 8.8, this poses a high risk to the confidentiality, integrity, and availability of network communications.

Immediate Action: Since no official patch is currently identified, isolate the affected device from the public internet and restrict management access to trusted internal IP addresses only. Contact the vendor directly to inquire about a firmware update that addresses the reported memory corruption.

Proactive Monitoring: Monitor network traffic for unusual POST requests directed at the /goform/fast_setting_wifi_set endpoint. Review system logs for unexpected crashes or service restarts that may indicate attempted buffer overflow exploitation.

Compensating Controls: Deploy a Web Application Firewall or network intrusion detection system with custom rules to filter or block requests containing excessively long strings in the ssid_5g parameter.

Public Exploit Available: Yes, a published proof-of-concept exists as documented in the linked GitHub repository.

The presence of a publicly available proof-of-concept elevates the risk of exploitation for this vulnerability. Administrators must prioritize the containment of all Tenda RX3 devices by removing them from public-facing configurations immediately. Until a vendor-supplied firmware update is verified and applied, strict network segmentation is the most effective method to mitigate the risk of remote compromise.