A critical stack-based buffer overflow vulnerability in Tenda FH1201 routers enables remote attackers to achieve arbitrary code execution or cause a denial of service.

This vulnerability is a stack-based buffer overflow (CWE-121) located in the formWrlExtraSet function within the /goform/WrlExtraSet endpoint. An attacker with low privileges can supply a maliciously crafted GO argument to trigger memory corruption, potentially leading to remote code execution.

Successful exploitation of this vulnerability poses a severe risk to network integrity and security. An attacker can gain control over the affected router, facilitating unauthorized access to internal network traffic, data interception, or the deployment of persistent threats within the environment. Given the CVSS score of 8.8, this flaw is categorized as High severity, necessitating immediate attention to prevent potential system compromise and unauthorized lateral movement.

Immediate Action: Contact the vendor for firmware updates addressing this buffer overflow. If no patch is currently available, restrict access to the device management interface to trusted internal segments only.

Proactive Monitoring: Monitor network traffic for unusual POST requests directed at the /goform/WrlExtraSet endpoint and inspect system logs for device crashes or unexpected reboots.

Compensating Controls: Implement a Web Application Firewall (WAF) or an Intrusion Prevention System (IPS) rule to filter or drop requests containing excessively long strings within the GO parameter.

Public Exploit Available: Yes, a proof-of-concept exploit is publicly available via a researcher write-up hosted on GitHub.

The presence of a public proof-of-concept significantly increases the risk of exploitation by opportunistic actors. Organizations currently using the Tenda FH1201 device should prioritize isolating the hardware from public-facing interfaces and verify vendor support channels for a firmware update. Failure to address this vulnerability may lead to complete compromise of the network gateway.