CVE-2026-13377

WatchGuard Firebox Stored Cross-Site-Scripting (XSS) Vulnerability in SIP Proxy Configuration

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 SIP Proxy module allows Stored XSS. This vulnerability is an additional unmitigated attack path for CVE-2025-6947.

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

References

https://psirt.watchguard.com/CVE-2026-13377vendor-advisory
https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00019vendor-advisory

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