A critical stack-based buffer overflow vulnerability in Tenda CH22 devices poses a significant risk of remote code execution and system compromise.

This vulnerability is a stack-based buffer overflow located in the formCertLocalPrecreate function within the /goform/CertLocalPrecreate endpoint. An attacker with low privileges can trigger this memory corruption by sending a specially crafted standard argument to the affected parameter, potentially leading to remote code execution.

The ability for an unauthenticated or low-privileged attacker to achieve remote code execution on a network device represents a severe threat to internal infrastructure. With a CVSS score of 8.8, this flaw could allow attackers to bypass perimeter security, intercept network traffic, or pivot further into the local network. Successful exploitation would likely result in complete loss of device control and potential compromise of connected systems.

Immediate Action: Contact Tenda support or monitor the official Tenda website for firmware updates addressing this vulnerability, as no official patch is currently listed. If an update is unavailable, restrict access to the web management interface to trusted administrative IP addresses only.

Proactive Monitoring: Review web access logs for unusual POST requests directed at the /goform/CertLocalPrecreate endpoint, specifically looking for abnormally long string patterns in the standard parameter.

Compensating Controls: Deploy a Web Application Firewall (WAF) or an Intrusion Prevention System (IPS) rule to inspect and block excessively long inputs sent to the /goform/CertLocalPrecreate path.

Public Exploit Available: Yes, a functional proof-of-concept is available via the researcher's published technical write-up on GitHub.

Given the availability of a public proof-of-concept and the high severity of remote code execution, security teams must treat this as a priority. Immediately isolate affected devices from external network exposure and monitor for any signs of anomalous traffic targeting the identified management function until a vendor-supplied firmware fix is applied.