CVE-2026-13377

Medium

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.

SeverityMedium

CVSS4.8

Exploit probability—

ProductWatchguard Fireware

PublishedJul 3, 2026

First seenJul 3, 2026

Weakness typeCWE-79Cross-site scripting (XSS)

How to fix

Update

watchguard fireware12.12.1, 2026.2.1 or later

Vendor advisories

psirt.watchguard.com/CVE-2026-13377
watchguard.com/wgrd-psirt/advisory/wgsa-2026-00019

Affected products

Product	Affected versions	Fixed in
watchguard fireware	12.0 ≤ v < 12.12.1, 2025.1 ≤ v < 2026.2.1, 12.5 ≤ v ≤ 12.5.18	12.12.1, 2026.2.1

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