A critical stack-based buffer overflow vulnerability in Tenda F456 allows remote attackers to execute arbitrary code or cause a denial of service.

The flaw resides in the fromqossetting function within the /goform/qossetting endpoint, where the page parameter is processed by a sprintf function without sufficient length validation. While the CVSS vector indicates low privilege requirements, the vulnerability is remotely exploitable and leads to memory corruption.

Successful exploitation of this vulnerability poses a severe risk to organizational infrastructure, as it enables remote code execution or persistent denial of service on network hardware. With a CVSS score of 8.8, this high-severity flaw could lead to full device compromise, allowing attackers to intercept traffic or pivot into internal network segments.

Immediate Action: Since no official patch is currently available, administrators should immediately restrict access to the web management interface of the affected Tenda F456 devices.

Proactive Monitoring: Monitor network traffic for suspicious POST requests directed at the /goform/qossetting URI, specifically looking for abnormally long string patterns in the page parameter.

Compensating Controls: Implement a Web Application Firewall (WAF) or equivalent network inspection rule to block requests containing malformed or excessively long arguments directed at the vulnerable endpoint.

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

Given the severity of this vulnerability and the availability of public proof-of-concept code, immediate action is required to prevent compromise. Organizations using the affected Tenda F456 hardware should isolate these devices from the public internet and restrict management access to trusted internal addresses until a vendor-supplied firmware update is deployed.