A critical stack-based buffer overflow in Tenda FH1201 and FH1206 routers permits remote attackers to execute arbitrary code or cause a denial of service via malformed HTTP requests.

This vulnerability is a stack-based buffer overflow occurring in the strcat function within the HTTP Request Handler. An authenticated user can trigger this memory corruption by sending a crafted HTTP GET request to the /goform/webtypelibrary endpoint with an excessively long webSiteId argument.

The ability for a remote attacker to achieve arbitrary code execution on networking infrastructure poses a severe risk to organizational security. Successful exploitation could lead to full device compromise, unauthorized network traffic interception, or persistent denial of service, severely impacting business operations. With a CVSS score of 8.8, this vulnerability is classified as High and demands immediate attention to prevent lateral movement within the local network.

Immediate Action: Since a specific patch version is currently unknown, administrators should immediately restrict access to the web management interface of affected Tenda routers to trusted management IP addresses only.

Proactive Monitoring: Review device logs for unusual HTTP GET requests targeting the /goform/webtypelibrary URI, specifically monitoring for anomalous lengths in the webSiteId parameter.

Compensating Controls: If management interface access cannot be restricted, ensure that the router is not exposed to the public internet and utilize network segmentation to isolate administrative traffic from user-facing segments.

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

Given the availability of public proof-of-concept code and the critical nature of buffer overflow vulnerabilities in network hardware, the risk is significant. Organizations using these Tenda devices must treat this as a priority, ensuring that administrative interfaces are not exposed to untrusted networks while awaiting official vendor firmware updates.