A critical stack-based buffer overflow vulnerability in Tenda CH22 routers may allow remote attackers to achieve arbitrary code execution or cause a denial of service.

The vulnerability exists within the formWrlExtraSet function of the /goform/WrlExtraSet endpoint, where the GO argument is processed without adequate length validation. This memory corruption flaw requires the attacker to have low-level privileges to interact with the vulnerable function, potentially leading to stack-based buffer overflow.

Successful exploitation of this vulnerability allows an attacker to compromise the integrity and availability of the affected network device. Given the CVSS score of 8.8, this represents a high-severity risk that could facilitate unauthorized remote code execution, leading to complete device takeover or systemic service disruption for connected users.

Immediate Action: As no official patch is currently confirmed, administrators should restrict network access to the management interface and the /goform/WrlExtraSet endpoint to trusted IP addresses only.

Proactive Monitoring: Review web server access logs for anomalous POST requests to /goform/WrlExtraSet, specifically monitoring for unusually large input values in the GO parameter.

Compensating Controls: Deploy a Web Application Firewall (WAF) rule to inspect and block incoming HTTP requests containing excessive data within the GO parameter field.

Public Exploit Available: Yes, a published proof-of-concept exists, as documented in the technical write-up provided by the vulnerability researcher.

Due to the high CVSS score and the public availability of exploit code, this vulnerability poses a significant risk to network infrastructure. Organizations using the Tenda CH22 device should prioritize isolating the management interface from the public internet and continue to monitor vendor channels for the release of an official firmware update.