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OpenAdvisories
High · 8.4 CVE-2026-4266 EUVD-2026-17079

WatchGuard Firebox Insecure Deserialization in Fireware Access Portal

Published Mar 30, 2026 · Updated Aug 27, 2026 · Assigned by WatchGuard

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.

Note, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T15 and T35.

Affected products

VendorProductAffectedFixed
WatchGuard Fireware OS 2025.1 – < 2026.2, 12.1 – < 12.12, 12.1 – < 12.11.9 2026.2

Advisories 1

References