A buffer overflow in the formL2TPSetup function of the Edimax BR-6428NS firmware allows a remote attacker to manipulate the L2TPUserName field in a POST request, potentially leading to arbitrary code execution on the router. The flaw arises from improper bounds checking (CWE-119) and unsafe memory handling (CWE-120). Because the vulnerable endpoint is reachable over the network, the impact escalates to remote code execution, compromising confidentiality, integrity and availability of the device.

The vulnerability affects the Edimax BR-6428NS router with firmware version 1.10. No other versions or variants are currently listed as impacted.

The CVSS score is 8.7, indicating high severity. The EPSS score is not available, but an exploit has been published and the vulnerability can be triggered remotely via a POST request to /goform/formL2TPSetup. The lack of a vendor response and the public availability of the exploit increase the risk of real-world attacks, although the exact exploitation probability cannot be quantified in the absence of EPSS data. The vulnerability is not yet listed in the CISA KEV catalog, but the combination of public exploit, high CVSS, and remote attack vector still warrants serious attention.