CVE-2026-3987

WatchGuard Firebox Arbitrary File Write vis Path Traversal in Fireware Web UI

Published Apr 1, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
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.

Analysis

AI-generated

Technical impact

A path traversal flaw in the Fireware OS Web UI allows an authenticated user with elevated privileges to overwrite arbitrary files on the device. The revised description confirms that this can lead to execution of malicious code within the context of an elevated system process, effectively granting the attacker full control over the firewall and undermining confidentiality, integrity, and availability.

Affected Systems

WatchGuard Fireware OS installations on Firebox devices.

Risk and Exploitability

The CVSS base score of 8.6 indicates a high severity vulnerability. The EPSS score of < 1% shows a very low but non-zero probability of exploitation. The vulnerability is not listed in the CISA KEV catalog. The flaw requires remote access to the Web UI and valid credentials with elevated privileges; thus, the attack vector is remote authenticated. Once an attacker authenticates, they can exploit the path traversal to place malicious files that the system process will execute.

Remediation

Vendor Solution

Fireware OS 2026.2, Fireware OS 12.12


OpenCVE Recommended Actions

  • Apply the latest Fireware OS firmware update that includes the fix, such as Fireware OS 12.12 or 2026.2.
  • Restrict access to the Web UI to trusted internal networks and enforce strong authentication.
  • Enforce least privilege on user accounts that can access the Web UI.

Generated by OpenCVE AI on August 10, 2026 at 23:48 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Watchguard firebox Cloud
Watchguard firebox M270
Watchguard firebox M290
Watchguard firebox M295
Watchguard firebox M370
Watchguard firebox M390
Watchguard firebox M395
Watchguard firebox M440
Watchguard firebox M4600
Watchguard firebox M470
Watchguard firebox M4800
Watchguard firebox M495
Watchguard firebox M5600
Watchguard firebox M570
Watchguard firebox M5800
Watchguard firebox M590
Watchguard firebox M595
Watchguard firebox M670
Watchguard firebox M690
Watchguard firebox M695
Watchguard firebox Nv5
Watchguard firebox T115-w
Watchguard firebox T125
Watchguard firebox T125-w
Watchguard firebox T145
Watchguard firebox T145-w
Watchguard firebox T185
Watchguard firebox T20
Watchguard firebox T25
Watchguard firebox T40
Watchguard firebox T45
Watchguard firebox T55
Watchguard firebox T70
Watchguard firebox T80
Watchguard firebox T85
Watchguard fireboxv
Watchguard fireware
CPEs cpe:2.3:a:watchguard:firebox_cloud:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m270:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m290:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m295:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m370:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m390:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m395:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m440:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m4600:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m470:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m4800:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m495:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m5600:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m570:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m5800:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m590:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m595:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m670:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m690:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_m695:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_nv5:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t115-w:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t125-w:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t125:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t145-w:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t145:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t185:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t20:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t25:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t40:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t45:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t55:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t70:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t80:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:firebox_t85:-:*:*:*:*:*:*:*
cpe:2.3:h:watchguard:fireboxv:-:*:*:*:*:*:*:*
cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:*
Vendors & Products Watchguard firebox Cloud
Watchguard firebox M270
Watchguard firebox M290
Watchguard firebox M295
Watchguard firebox M370
Watchguard firebox M390
Watchguard firebox M395
Watchguard firebox M440
Watchguard firebox M4600
Watchguard firebox M470
Watchguard firebox M4800
Watchguard firebox M495
Watchguard firebox M5600
Watchguard firebox M570
Watchguard firebox M5800
Watchguard firebox M590
Watchguard firebox M595
Watchguard firebox M670
Watchguard firebox M690
Watchguard firebox M695
Watchguard firebox Nv5
Watchguard firebox T115-w
Watchguard firebox T125
Watchguard firebox T125-w
Watchguard firebox T145
Watchguard firebox T145-w
Watchguard firebox T185
Watchguard firebox T20
Watchguard firebox T25
Watchguard firebox T40
Watchguard firebox T45
Watchguard firebox T55
Watchguard firebox T70
Watchguard firebox T80
Watchguard firebox T85
Watchguard fireboxv
Watchguard fireware
Metrics cvssV3_1

{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
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.This issue affects Fireware OS 12.6.1 up to and including 12.11.8 and 2025.1 up to and including 2026.1.2. 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.
CPEs cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.6.1
cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:2025.1
cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:*
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.This issue affects Fireware OS 12.6.1 up to and including 12.11.8 and 2025.1 up to and including 2026.1.2.
Title WatchGuard Firebox Arbitrary File Write vis Path Traversal in Fireware Web UI
First Time appeared Watchguard
Watchguard fireware Os
Weaknesses CWE-22
CPEs cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.6.1
cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:2025.1
Vendors & Products Watchguard
Watchguard fireware Os
References
Metrics cvssV4_0

{'score': 8.6, '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'}

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Sources

Status
PUBLISHED
Assigner
WatchGuard
Published
Updated
Aug 10, 2026, 4:46 PM
Reserved
Mar 11, 2026, 3:01 PM
Status
Analyzed
Published
Apr 1, 2026, 10:16 PM
Modified
Oct 26, 2026, 9:10 PM