CVE-2026-3343#

WatchGuard Firebox Reflected Cross-Site-Scripting (XSS) Vulnerability in Fireware Web UI

Medium 5.1 CVSS v4.0 › Published 2026-03-03Updated 2026-08-10

Summary #

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.

Product status #

Product	Affected	Not affected
Fireware OS
Default	>= 2025.1, < 2026.1.2, >= 12.7, < 12.11.8	>= 2026.1.2, >= 12.11.8

Weakness Type and Impact #

CWECWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPECCAPEC-591Reflected XSS

Exploitation Status #

WatchGuard is not aware of any exploitation of this issue in the wild.

Solution #

Fireware OS 2026.1.2, Fireware OS 12.11.8

References #

https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00004

Credits #

btaolfinder