CVE-2026-13728 fireware vulnerability
In exception circumstances, WatchGuard Fireware OS on a FireCluster may use a hard-coded encryption key to encrypt saved credentials for Access Portal resources. This vulnerability affects Fireware OS 12.1 up to and including 12.12 and 2025.1 up to and including 2026.2. This vulnerability does not affect devices that do not support the Access Portal feature or standalone Fireboxes not deployed in a FireCluster.
Quick answer
watchguard fireware should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Fireware OS 12.0 through 12.12
- Fireware OS 2025.1 through 2026.2
Fixed versions
- Fireware OS 12.12.1 or later
- Fireware OS 2026.2.1 or later
How to fix it
CVE-2026-13728 affects watchguard fireware. The affected range is Fireware OS 12.0 through 12.12, Fireware OS 2025.1 through 2026.2. Update to Fireware OS 12.12.1 or later, Fireware OS 2026.2.1 or later. Treat exposed systems first, especially where management, VPN, and firewall admin access can be reached. If you suspect abuse, review logs and rotate secrets that may have been exposed.
- Inventory every watchguard fireware install and note the exact version.
- Compare each install with the affected range: Fireware OS 12.0 through 12.12, Fireware OS 2025.1 through 2026.2.
- Update to Fireware OS 12.12.1 or later, Fireware OS 2026.2.1 or later.
- If you cannot patch today, restrict management, VPN, and firewall admin access to trusted users and networks.
- Back up the current configuration before changing production systems.
- Review recent logs for errors, crashes, strange admin activity, or unexpected outbound connections.
- Rotate passwords, tokens, and keys if the system may have been exposed or abused.
- Document the change, owner, date, and final version.
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Verify the fix
- Confirm the installed version now matches the fixed guidance: Fireware OS 12.12.1 or later, Fireware OS 2026.2.1 or later.
- Confirm old affected versions are no longer deployed: Fireware OS 12.0 through 12.12, Fireware OS 2025.1 through 2026.2.
- Confirm management, VPN, and firewall admin access is limited to the smallest needed group.
- Rerun the relevant Fixnx scan or internal check after the change.
- Save logs, screenshots, or package output as proof of the fix.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-13728?
watchguard fireware versions listed as affected should be reviewed: Fireware OS 12.0 through 12.12, Fireware OS 2025.1 through 2026.2.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.