A stack‑based buffer overflow in the iked process of WatchGuard Fireware OS allows a remote attacker to send specially crafted network traffic and execute arbitrary code without authentication. The vulnerability results from improper handling of input that overflows a buffer on the stack, leading to control‑flow hijacking and potentially full system compromise. The effect on confidentiality, integrity, and availability is total, as an attacker who succeeds can take control of the device and disrupt network services.

WatchGuard Fireware OS devices are affected, including versions prior to Fireware OS 2026.2.2, Fireware OS 12.12.2, and Fireware OS 12.5.20. All releases before these patches are vulnerable.

With a CVSS score of 9.3 the vulnerability is classified as critical. EPSS data is not available, but the CVE has not been listed in the CISA KEV catalog. The likely attack vector is remote network traffic directed at the iked service, and the flaw can be exploited by unauthenticated attackers who can craft packets that trigger a stack overflow and gain arbitrary code execution on the affected device.