This vulnerability (CVE-2026-8247) is a classic buffer overflow (CWE-120) in WatchGuard Fireware OS. It allows an unauthenticated attacker on the same local network segment to perform an out-of-bounds write, potentially leading to arbitrary code execution. The affected versions include 11.0 up to 11.12.4_Update1, 12.0 up to 12.12, and 2025.1 up to 2026.2. The CVSS 4.0 base score is 7.7, indicating high severity, with attack vector being adjacent network, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. There is no vendor advisory or patch information available at this time, and no known exploits in the wild have been reported.

Successful exploitation allows an unauthenticated attacker on the same local network segment to execute arbitrary code on the affected Fireware OS device. This can lead to full compromise of the device, impacting confidentiality, integrity, and availability of network security functions.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, limit network exposure of affected Fireware OS devices to trusted networks only and monitor for unusual activity. Avoid placing these devices on untrusted local network segments.