Medium severity · published Mar 3, 2026
CVE-2026-3343
WatchGuard Firebox Reflected Cross-Site-Scripting (XSS) Vulnerability in Fireware Web UI
6.1
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% 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 2026.1.2; 12.7 before 12.11.8 · source: vendor
FI
Fireware · Watchguard
12.7 before 12.11.8; 2025.1 before 2026.1.2 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3343
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-3343
psirt.watchguard.com
https://psirt.watchguard.com/CVE-2026-3343
Vendor Advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00004
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