A critical stack-based buffer overflow vulnerability in Tenda AC8 routers permits remote memory corruption and potential code execution.

The vulnerability exists within the webCgiGetUploadFile function of the /cgi-bin/UploadCfg endpoint in the Httpd service. An authenticated attacker can trigger a stack-based buffer overflow by manipulating the boundary argument.

This vulnerability poses a significant risk to network integrity, as successful exploitation can lead to arbitrary code execution or complete system compromise. With a CVSS score of 8.8, this flaw represents a high-severity risk that could result in unauthorized access to internal network traffic or the total loss of device availability, causing operational disruption.

Immediate Action: Since no specific patch is currently identified, administrators should immediately restrict access to the web management interface of the Tenda AC8 to trusted internal networks only.

Proactive Monitoring: Security teams should monitor device logs for repeated crashes of the Httpd service or unusual traffic patterns directed at the /cgi-bin/UploadCfg endpoint.

Compensating Controls: Deploy a Web Application Firewall (WAF) or network-based Intrusion Prevention System (IPS) configured to inspect HTTP requests for oversized boundary parameters directed at the management interface.

Public Exploit Available: Yes, a published proof-of-concept exists as documented in the research write-up at GitHub.

Given the availability of public proof-of-concept code and the potential for remote memory corruption, this vulnerability requires immediate attention. Organizations utilizing the affected Tenda AC8 firmware should isolate the management interface from the public internet and maintain a heightened state of vigilance until the vendor releases a security update that addresses the overflow condition in the UploadCfg function.