Deserialization of Untrusted Data in Fireware OS - CVE-2026-4266
Published: March 27, 2026
Vulnerability identifier: #VU124662
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-4266
CWE-ID: CWE-502
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: WatchGuard
Affected software:
Fireware OS
Fireware OS
Detailed vulnerability description
The vulnerability allows a local user to execute arbitrary code on the target system.
The vulnerability exists due to insecure input validation when processing serialized data in Fireware Access Portal. A local administrator can pass specially crafted data to the application and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
How to mitigate CVE-2026-4266
Install updates from vendor's website.