Firebox and Fireware OS
CVE-2025-6999: WatchGuard Firebox Authentication Portal Request Smuggling Vulnerability
An HTTP Request Smuggling [CWE-444] vulnerability in the Authentication portal of WatchGuard Fireware OS allows a remote attacker to evade request parameter sanitation and perform a reflected self-Cross-Site Scripting (XSS) attack.
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 12.0 | 12.11.3 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
An HTTP Request Smuggling [CWE-444] vulnerability in the Authentication portal of WatchGuard Fireware OS allows a remote attacker to evade request parameter sanitation and perform a reflected self-Cross-Site Scripting (XSS) attack.
WatchGuard does not believe there is a practical exploit chain with a meaningful security impact for this vulnerability.
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.