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.
Published: 2026-03-30
Score: 8.4 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

Fireware OS 2026.2, Fireware OS 12.12

Tracking

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Advisories

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History

Mon, 10 Aug 2026 17:00:00 +0000

Type Values Removed Values Added
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. 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.
CPEs cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.1
cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:2025.1
cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:*
References

Mon, 30 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Mon, 30 Mar 2026 13:00:00 +0000

Type Values Removed Values Added
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.
Title WatchGuard Firebox Insecure Deserialization in Fireware Access Portal
First Time appeared Watchguard
Watchguard fireware Os
Weaknesses CWE-502
CPEs cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:12.1
cpe:2.3:a:watchguard:fireware_os:*:*:*:*:*:*:*:2025.1
Vendors & Products Watchguard
Watchguard fireware Os
References
Metrics cvssV4_0

{'score': 8.4, 'vector': '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'}


Subscriptions

Watchguard Fireware Os
cve-icon MITRE

Status: PUBLISHED

Assigner: WatchGuard

Published:

Updated: 2026-08-10T16:39:49.547Z

Reserved: 2026-03-16T12:50:10.806Z

Link: CVE-2026-4266

cve-icon Vulnrichment

Updated: 2026-03-30T13:19:52.252Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-30T13:16:22.573

Modified: 2026-08-10T17:17:34.917

Link: CVE-2026-4266

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-11T00:00:08Z

Weaknesses