Overview
CVE-2025-13940 is a security vulnerability affecting WatchGuard Fireware OS. This vulnerability, classified as an Expected Behavior Violation [CWE-440], allows a potential attacker to bypass the Fireware OS boot-time system integrity check. This bypass can prevent the Firebox from shutting down, even if the system integrity check fails.
While the on-demand system integrity check in the Fireware Web UI will correctly display a failed system integrity check message, the underlying protection mechanism during boot may be compromised.
Technical Details
The vulnerability resides in the boot process of WatchGuard Fireware OS. Specifically, the flaw allows an attacker to potentially circumvent the intended system integrity verification that is performed during boot. Successfully exploiting this vulnerability would prevent the device from automatically shutting down in the event that the integrity check fails as designed.
Affected Versions:
- Fireware OS: from 12.8.1 through 12.11.4
- Fireware OS: from 2025.1 through 2025.1.2
CVSS Analysis
Currently, a CVSS score is not available for CVE-2025-13940. This does not diminish the potential risk. It is crucial to analyze this in your specific context. WatchGuard may update the advisory with a CVSS score at a later date.
Possible Impact
The primary impact of this vulnerability is a potential compromise of the system’s integrity protection mechanism. If successfully exploited, an attacker could potentially:
- Prevent the Firebox from shutting down in the event of a compromised system.
- Potentially load and execute malicious code undetected during the boot process.
- Lead to further exploitation and compromise of the network protected by the Firebox.
Mitigation or Patch Steps
The recommended mitigation is to upgrade your WatchGuard Fireware OS to a version that is not affected by CVE-2025-13940. Refer to the WatchGuard security advisory for specific upgrade instructions and the fixed versions. Check the WatchGuard portal for firmware upgrades.
Until you can upgrade, consider closely monitoring your WatchGuard Firebox logs for any suspicious activity that could indicate a compromise. Pay particular attention to boot-related events and any indications of system tampering.
