Firebox and Fireware OS
CVE-2026-3987: WatchGuard Firebox Arbitrary File Write vis Path Traversal in Fireware Web UI
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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Fireware OS 2025.1 | 2026.2 or later |
| Fireware OS 12.6 | 12.12 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Exploitation
WatchGuard is not aware of any exploitation of this issue in the wild.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.