CVE-2026-13371 WatchGuard Firebox Management Web UI Denial of Service via Unsafe Deserialization

What is CVE-2026-13371?

CVE-2026-13371 is a medium-severity unsafe deserialization vulnerability in Watchguard Fireware, published on 2 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

An authenticated administrator can trigger a denial-of-service condition in the Fireware Management Web UI by sending malformed or crafted data to the put_data endpoint, which performs unsafe deserialization of the attacker-supplied input.

Weakness: CWE-502

Which versions are affected by CVE-2026-13371?

It affects 1 product.

Products include Watchguard Fireware.

How do I fix CVE-2026-13371?

No fix has been published for CVE-2026-13371 yet. Limit exposure of the affected software until one is available.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2026-13371 being exploited?

There is no known exploitation of CVE-2026-13371 in the wild and no public exploit code.

Other vulnerabilities in Watchguard Fireware

• CVE-2022-26318 WatchGuard Firebox and XTM Appliances Arbitrary Code Execution Exploited Critical 9.8
• CVE-2025-14733 WatchGuard Firebox Out of Bounds Write Exploited Critical 9.3
• CVE-2025-9242 WatchGuard Firebox Out-of-Bounds Write Exploited Critical 9.3
• CVE-2022-23176 WatchGuard Firebox and XTM Privilege Escalation Exploited High 8.8
• CVE-2022-31789 Integer overflow in n/a Critical 9.8

All Watchguard Fireware vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-hprc-6hj7-jj8j.