CVE-2026-13376

WatchGuard Firebox Stored Cross-Site-Scripting (XSS) Vulnerability in spamBlocker Module

State: Published
Severity: 4.8 Medium
Published: Jul 2, 2026
Updated: Aug 27, 2026
Reserved: Jun 25, 2026

Description

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in WatchGuard Fireware OS spamBlocker module allows Stored XSS. This vulnerability is an additional unmitigated attack path for CVE-2025-1071.

This issue affects Fireware OS 12.0 up to and including 12.12, 12.5 up to and including 12.5.18, and 2025.1 up to and including 2026.2.

Scores

CVSS	Score	Vector	Source
4.0	4.8 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N	WatchGuard

Weaknesses

CWE-79

Affected Products

Product	Versions
Fireware OSWatchGuard	2025.1 to before 2026.2.1Affected 12.0 to before 12.12.1Affected
Fireware OSWatchGuard	12.0 to before 12.11.9Affected
Fireware OSWatchGuard	12.0 to before 12.5.19Affected

References

https://psirt.watchguard.com/CVE-2026-13376vendor-advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00018vendor-advisory

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