CVE-2025-6999

WatchGuard Firebox Authentication Portal Request Smuggling Vulnerability

Medium 6.9 CVSS v4.0 › Published 2025-09-15Updated 2026-08-10

Summary #

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.

Product status #

ProductAffectedNot affected
Fireware OS>= 12.0, < 12.11.3>= 12.11.3

Weakness Type and Impact #

  • CWECWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
  • CAPECCAPEC-63Cross-Site Scripting (XSS)

Exploitation Status #

WatchGuard is not aware of any exploitation of this vulnerability in the wild.

Solution #

Fireware OS 12.11.3

References #