CVE-2026-4266

HIGH

WatchGuard Firebox Insecure Deserialization in Fireware Access Portal

Title source: cna
STIX 2.1

Description

An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user.This issue affects Fireware OS: 12.1 through 12.11.8 and 2025.1 through 2026.1.2. Note, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T-15 and T-35.

References (1)

Core 1
Core References

Scores

CVSS v4 8.4
EPSS 0.0029
EPSS Percentile 20.1%
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

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-502
Status published
Products (2)
WatchGuard/Fireware OS 12.1 - 12.11.8
WatchGuard/Fireware OS 2025.1 - 2026.1.2
Published Mar 30, 2026
Tracked Since Mar 30, 2026