Firebox and Fireware OS
CVE-2026-13376: WatchGuard Firebox Stored Cross-Site-Scripting (XSS) Vulnerability in spamBlocker Module
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in WatchGuard Fireware OS spamBlocker module allows Stored XSS.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Fireware OS (Default) 2025.1 | 2026.2.1 or later |
| Fireware OS (Default) 12.0 | 12.12.1 or later |
| Fireware OS (EUCC) 12.0 | 12.11.9 or later |
| Fireware OS (T15/T35) 12.0 | 12.5.19 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Exploitation
WatchGuard is not aware of any exploitation of this vulnerability in the wild.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.