CVE-2026-3343: WatchGuard Firebox Reflected Cross-Site-Scripting (XSS) Vulnerability in Fireware Web UI

Published Mar 3, 2026
·
Updated

A reflected cross-site scripting (XSS) vulnerability in the Fireware OS Web UI enabled execution of malicious JavaScript in the context of an authenticated management user's browser when they click on a specially crafted link.

This vulnerability affects Fireware OS 12.7 up to and including 12.11.7 and 2025.1 up to and including 2026.1.1.

Affected Software

39 affected components
WatchGuard Fireware OS>=12.7<=12.11.7, >=2025.1<=2026.1.1
All of the following
WatchGuard Fireware>=12.7<12.11.8
Any of the following
WatchGuard Firebox M270
WatchGuard Firebox M290
WatchGuard Firebox M370
WatchGuard Firebox M390
WatchGuard Firebox M440
WatchGuard Firebox M4600
WatchGuard Firebox M470
WatchGuard Firebox M4800
WatchGuard Firebox M5600
WatchGuard Firebox M570
WatchGuard Firebox M5800
WatchGuard Firebox M590
WatchGuard Firebox M670
WatchGuard Firebox M690
WatchGuard Firebox Nv5
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 Fireboxcloud
WatchGuard Fireboxv
All of the following
WatchGuard Fireware>=2025.1<2026.1.2
Any of the following
WatchGuard Firebox M295
WatchGuard Firebox M395
WatchGuard Firebox M495
WatchGuard Firebox M595
WatchGuard Firebox M695
WatchGuard Firebox T115-w
WatchGuard Firebox T125
WatchGuard Firebox T125-w
WatchGuard Firebox T145
WatchGuard Firebox T145-w
WatchGuard Firebox T185

Event History

Mar 3, 2026
CVE Published
via MITRE·01:17 PM
Data Sourced
via MITRE·01:17 PM
DescriptionWeakness
Data Sourced
via NVD·02:15 PM
DescriptionSeverityWeaknessAffected Software
Jul 22, 58183
Event
via NVD·03:02 AM
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Frequently Asked Questions

1

What is the severity of CVE-2026-3343?

CVE-2026-3343 has been rated as medium severity due to its potential to execute malicious JavaScript in an authenticated user's browser.

2

How do I fix CVE-2026-3343?

To fix CVE-2026-3343, users should upgrade to Fireware OS versions 12.11.8 or later, or 2026.1.2 or later.

3

Who is affected by CVE-2026-3343?

CVE-2026-3343 affects authenticated users of the Fireware Web UI across several Firebox models running vulnerable versions of Fireware OS.

4

What type of vulnerability is CVE-2026-3343?

CVE-2026-3343 is categorized as a reflected cross-site scripting (XSS) vulnerability.

5

What can attackers achieve with CVE-2026-3343?

Attackers can execute arbitrary JavaScript in the context of an authenticated management user's browser, potentially leading to data theft or manipulation.

Contact

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