CVE-2026-4266

HIGH EPSS 20.3%

Published Mar 30, 20263mo ago · Modified Jun 17, 20261w ago

8.4 CVSS 4.0

High

Published Mar 30, 2026 3mo ago

Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score

8.4

Exploitability

—

Impact

—

Vector string

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:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector Local

Attack Complexity Low

Privileges Required High

User Interaction None

Scope X

Threat Intelligence

EPSS Exploit Probability

20.3% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-502 Deserialization of Untrusted Data Validation

References 1

watchguard.com https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00007

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.