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

Vulnerability summary

CVE-2025-9242 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in WatchGuard Firebox. It is known to be exploited: CISA lists it, first on 12-11-2025. EPSS estimates a 91.80% chance of exploitation in the next 30 days, higher than 99.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 17-09-2025
   PublishedVulnerability first disclosed.
2. 12-11-2025
   Added to CISA KEVWatchGuard Firebox Out-of-Bounds Write Vulnerability
3. 03-12-2025
   CISA remediation dueApply mitigations per vendor instructions.
4. 10-08-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.