A critical stack-based buffer overflow vulnerability in the Tenda CH22 router allows authenticated attackers to execute arbitrary code or crash the system.

The vulnerability exists within the fromSetCfm function in the /goform/setcfm endpoint, where the funcpara1 parameter is processed without adequate length validation. This memory corruption flaw, classified as a stack-based buffer overflow, requires the attacker to have low-level access to the device to trigger the malicious payload.

Successful exploitation of this vulnerability can result in full system compromise, including remote code execution (RCE) or persistent denial of service (DoS). Given the CVSS score of 8.8, this represents a high-severity threat that could lead to unauthorized network control or data interception. Organizations relying on these devices should treat this as a significant risk to internal network integrity.

Immediate Action: Contact Tenda support or check the official vendor portal for firmware updates addressing this buffer overflow, as no public patch is currently confirmed. Until a patch is applied, restrict access to the web management interface to trusted internal segments only.

Proactive Monitoring: Review web server access logs for anomalous POST requests to the /goform/setcfm endpoint, particularly those containing excessively long parameter strings.

Compensating Controls: Implement network-level access control lists (ACLs) to prevent unauthorized devices from reaching the administrative interface of the router.

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

Due to the availability of a public proof-of-concept and the potential for remote code execution, this vulnerability poses a severe risk to affected Tenda CH22 devices. Administrators must prioritize isolating these devices from external networks and remain vigilant for vendor-issued firmware updates to remediate the underlying memory corruption flaw.