High 8.6Published Apr 1, 2026

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

Updated under an hour ago (Oct 26, 2026, 7:00 PM ET)

Does this affect you?

It affects WatchGuard Fireware OS and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for WatchGuard Fireware OS

Exploited in the last 30 days

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.

CVSS: 8.6 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-22
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: WatchGuard
NVD analysis: Analyzed
Record last updated: Aug 10, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

WatchGuard Fireware OS watchguard:fireware_os (from the name)	from 2025.1 before 2026.2; from 12.6.1 before 12.12	CNA record
watchguard fireware watchguard:fireware	from 2025.1 before 2026.2; from 12.6.1 before 12.12	NVD

References

References

https://psirt.watchguard.com/CVE-2026-3987	vendor-advisory, broken-link
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00009	vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.