Cross-site scripting in Fireware OS - CVE-2026-13377
Published: July 3, 2026
Vulnerability identifier: #VU136883
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-13377
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: WatchGuard
Affected software:
Fireware OS
Fireware OS
Detailed vulnerability description
The vulnerability allows a remote user to inject arbitrary script code into generated web pages.
The vulnerability exists due to cross-site scripting in the SIP Proxy module when generating web pages from stored configuration input. A remote privileged user can inject a specially crafted payload to inject arbitrary script code into generated web pages.
This issue is described as an additional unmitigated attack path for CVE-2025-6947.
How to mitigate CVE-2026-13377
Install security update from vendor's website.