CVE-2026-18105: WatchGuard Fireware

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

An uncontrolled resource consumption vulnerability in Fireware OS's diagnostic tasks feature allows a low-privileged, authenticated user to cause a denial of service of the system's diagnostic tools by repeatedly starting and aborting a specially crafted diagnostic task through the web UI.

Affected products

• WatchGuard Fireware: from 12.0, before 12.5.21 (fixed in 12.5.21); from 12.12, before 12.12.3 (fixed in 12.12.3); from 2025.0, before 2026.2.3 (fixed in 2026.2.3); from 2026.3, before 2026.3.2 (fixed in 2026.3.2)

Published 2026-09-30. Last modified 2026-10-08.