SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-3987

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.

HIGH 8.6EPSS 0.68%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.68%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0
8.6 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.68% probability · 50th percentile
CISA KEV
Not listed
Weakness
CWE-22
Affected
watchguard/fireware
Source
5d1c2695-1a31-4499-88ae-e847036fd7e3

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.