A stack-based buffer overflow exists in the D‑Link DIR‑816 1.10CNB05 firmware in the file /goform/form2Wl5RepeaterStep2.cgi of the goahead component. Manipulation of the arguments key1, key2, key3, key4, and pskValue can overflow a stack buffer, providing an attacker with the potential to inject and execute arbitrary code. The vulnerability is reported as exploitable remotely, meaning an attacker can trigger the overflow over the network without local access. The primary impact is the compromise of confidentiality, integrity, and availability of the affected device, potentially allowing full remote takeover of the router.

The vulnerable product is D‑Link DIR‑816 running firmware version 1.10CNB05. No other versions or products are listed in the CNA data. The vulnerability is limited to revisions that are no longer supported by the maintainer.

The CVSS score is 9.3, indicating critical severity. Although the EPSS score is less than 1%, indicating low probability of exploitation in the general population, the vulnerability is publicly available and could be used in targeted attacks. It is not listed in the CISA KEV catalog. The likely attack vector is remote network access via the router’s web interface to the vulnerable CGI endpoint.