A stack‑based buffer overflow exists in the formWifiMacFilterSet handler of the Tenda W3 router. A crafted POST request to the /goform/WifiMacFilterSet endpoint can overwrite critical stack memory, enabling an attacker to execute arbitrary code. Public exploits demonstrate that the overflow can be triggered remotely, potentially allowing full control of the device.

The vulnerability affects Tenda W3 routers running firmware version 1.0.0.3(2204). The flaw resides in the POST Parameter Handler component that exposes the /goform/WifiMacFilterSet endpoint via the web interface. Devices using the stated firmware revision are at risk if the endpoint is reachable from a network.

The CVSS score of 8.7 signals high severity, yet the EPSS score below 1% indicates a low current exploitation probability. The vulnerability is not listed in CISA’s KEV catalog, but publicly available exploits exist on GitHub. Attackers can exploit the flaw remotely through the web interface, so any host with network access to the router could target it. Overall, the risk is moderate to high, depending on network exposure and threat actor motivation.