A critical stack-based buffer overflow vulnerability in the Tenda F456 router enables remote code execution and requires immediate attention.

This is a stack-based buffer overflow (CWE-121) occurring in the formWebTypeLibrary function within the /goform/webtypelibrary endpoint. An authenticated attacker can trigger the overflow by supplying an overly long webSiteId parameter, which is processed without proper length validation.

The ability for an attacker to achieve remote code execution on network infrastructure poses a severe risk to organizational security. Successful exploitation could lead to full device compromise, potential lateral movement into the internal network, and significant disruption of internet connectivity, justifying the high CVSS score of 8.8.

Immediate Action: As no official patch is currently available, administrators should immediately restrict access to the web management interface of the Tenda F456 to trusted management subnets only.

Proactive Monitoring: Monitor device traffic for anomalous POST requests directed at the /goform/webtypelibrary endpoint, particularly those containing excessively large parameter strings.

Compensating Controls: Deploy a Web Application Firewall or an Intrusion Prevention System with rules configured to block or truncate long input strings sent to router administrative endpoints.

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

Given the availability of a public proof-of-concept and the potential for remote code execution, this vulnerability represents a significant risk to the integrity of the Tenda F456 device. Administrators must prioritize limiting access to the management interface until the vendor releases a firmware update that addresses the underlying buffer overflow.