The Tenda CX12L router firmware 16.03.53.12 contains a stack-based buffer overflow vulnerability in the form_fast_setting_wifi_set function within the /goform/fast_setting_wifi_set endpoint. This vulnerability arises from improper validation or handling of the ssid parameter, allowing an attacker to overflow the stack buffer remotely. The vulnerability has a CVSS 4.0 base score of 8.7, indicating high severity with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. The vulnerability is publicly disclosed but lacks an official patch or remediation from the vendor.

Successful exploitation of this vulnerability could allow a remote attacker to execute arbitrary code on the affected device, potentially leading to full compromise of the router. This could result in unauthorized access to network traffic, disruption of network services, or further attacks on connected devices. The vulnerability affects confidentiality, integrity, and availability of the device and network.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should consider limiting network exposure of the affected device, such as restricting remote management access or isolating the device in a segmented network environment. Monitor vendor channels for updates and apply patches promptly once available.