The Tenda W6-S wireless access point is vulnerable to a critical stack-based buffer overflow that may allow remote code execution.

The vulnerability exists in the formwrlSSIDset function, which uses the unsafe sprintf function to copy user-supplied 'GO' and 'index' parameters into a fixed-size 64-byte stack buffer. This allows an unauthenticated attacker to overwrite the stack, potentially leading to arbitrary code execution.

Exploitation of this buffer overflow could lead to a full device takeover or permanent denial of service. Because the device is a network infrastructure component, successful compromise could facilitate man-in-the-middle attacks or provide a persistent foothold within the local network, justifying the critical 9.8 CVSS score.

Immediate Action: Since a specific patch is not currently available, isolate the management interface of affected devices from the public internet and untrusted networks.

Proactive Monitoring: Monitor network traffic for malformed HTTP requests directed at the /goform/wifiSSIDset endpoint.

Compensating Controls: Restrict access to the device management interface to a dedicated, secure management VLAN and implement strict source IP filtering.

Public Exploit Available: Yes, a public proof-of-concept exists on GitHub.

Due to the availability of a public proof-of-concept and the lack of a vendor-provided patch, immediate network segmentation is required. Administrators should restrict management access to the affected Tenda devices until a firmware update addressing the buffer overflow is released.