CVE-2026-3987 WatchGuard Firebox Arbitrary File Write vis Path Traversal in Fireware Web UI

What is CVE-2026-3987?

CVE-2026-3987 is a high-severity path traversal vulnerability in Watchguard Fireware, published on 1 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

A path traversal vulnerability in the Fireware OS Web UI on WatchGuard Firebox systems may allow a privileged authenticated remote attacker to execute arbitrary code in the context of an elevated system process.

Weakness: CWE-22

Which versions are affected by CVE-2026-3987?

It affects 1 product.

Products include Watchguard Fireware.

How do I fix CVE-2026-3987?

No fix has been published for CVE-2026-3987 yet. Limit exposure of the affected software until one is available.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2026-3987 being exploited?

There is no known exploitation of CVE-2026-3987 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-8r96-cj5h-474x.