CVE-2025-9242: WatchGuard Firebox Out-of-Bounds Write Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2025-11-12. EPSS: 91.3% chance of exploitation in the next 30 days.

An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code. This vulnerability affects both the mobile user VPN with IKEv2 and the branch office VPN using IKEv2 when configured with a dynamic gateway peer. If the Firebox was previously configured with the mobile user VPN with IKEv2 or a branch office VPN using IKEv2 to a dynamic gateway peer, and both of those configurations have since been deleted, that Firebox may still be vulnerable if a branch office VPN to a static gateway peer is still configured.

Affected products

• WatchGuard Fireware: from 11.10.2, before 12.11.4 (fixed in 12.11.4); from 11.10.2, before 12.5.13 (fixed in 12.5.13); version 2025.1 only

Published 2025-09-17. Last modified 2026-08-10.