High severity · published Apr 1, 2026
CVE-2026-3987
WatchGuard Firebox Arbitrary File Write vis Path Traversal in Fireware Web UI
7.2
CVSS
0.7%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FO
Fireware OS · WatchGuard
2025.1 before 2026.2; 12.6.1 before 12.12 · source: vendor
FI
Fireware · Watchguard
2025.1 before 2026.2; 12.6.1 before 12.12 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3987
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3987
Broken Link
https://psirt.watchguard.com/CVE-2026-3987
Vendor Advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00009
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