Vulnerability · Published Apr 1, 2026 · Assigned by WatchGuard
CVE-2026-3987WatchGuard Firebox Arbitrary File Write vis Path Traversal in Fireware Web UI
High 8.6
In plain English
A high-severity path traversal in Fireware OS from WatchGuard. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities).
Severity (CVSS 4.0)8.6High
Exploit odds (30 days)0.7%top 47.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| WatchGuard | Fireware OS | 2025.1 – before 2026.212.6.1 – before 12.12 |
Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
- https://psirt.watchguard.com/CVE-2026-3987 vendor-advisory
- https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00009 vendor-advisory