A stack‑based buffer overflow exists in the formCrossBandSwitch function of Belkin F9K1122 firmware 1.00.33. By sending a maliciously constructed webpage argument to /goform/formCrossBandSwitch the attack can overflow the stack and overwrite control data, enabling an attacker to execute arbitrary code or crash the device. The flaw originates from improper input validation (CWE‑119, CWE‑121) and would allow a threat actor to gain full control over the device’s firmware, compromising confidentiality, integrity, and availability.

The vulnerability is specific to Belkin’s F9K1122 model running firmware version 1.00.33. No other versions are presently documented as affected.

With a CVSS score of 8.7 the flaw is considered high severity. The exploit is available publicly and can be triggered remotely via crafted HTTP requests to the compromised endpoint; no local privilege escalation or social‑engineering is required. Because the vulnerability is not listed in the KEV catalog and EPSS data is missing, the risk is judged to be high but the exact likelihood is undetermined. Immediate attention is required to mitigate potential exploitation.