CVE-2026-3343

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

At a glance

Severity: MEDIUM 5.1
EPSS: EPSS 0.21 % · percentile 12 (2026-10-27)
State: PUBLISHED
Published: 2026-03-03
Updated: 2026-08-10
Assigner: WatchGuard
NVD status: Modified

Description

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.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	MEDIUM 5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N	WatchGuard
CVSS 4.0	MEDIUM 5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD · 5d1c2695-1a31-4499-88ae-e847036fd7e3 (Secondary)
CVSS 3.1	MEDIUM 6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-79

European references

ENISA EUVD · EUVD-2026-9289
GCVE · GCVE-0-2026-3343

Affected configurations (NVD CPE)

cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:* ≥ 12.7 < 12.11.8
cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:* ≥ 2025.1 < 2026.1.2

Affected products

Product	Versions
WatchGuard · Fireware OS	affected 2025.1 < 2026.1.2 ; affected 12.7 < 12.11.8

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD