WatchGuard Firebox Insecure Deserialization in Fireware Access Portal

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Summary

CVECVE-2026-4266
StatePUBLISHED
AssignerWatchGuard
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-30 13:16:22 UTC
Updated2026-03-30 13:26:07 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v4.0 8.4 HIGH from 5d1c2695-1a31-4499-88ae-e847036fd7e3

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

EPSS: 0.000670000 probability, percentile 0.205930000 (date 2026-04-01)

Problem Types: CWE-502 | CWE-502 CWE-502 Deserialization of Untrusted Data

VersionSourceTypeScoreSeverityVector
4.05d1c2695-1a31-4499-88ae-e847036fd7e3Secondary8.4HIGHCVSS: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/C...
4.0CNACVSS8.4HIGHCVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
High
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA WatchGuard Fireware OS affected 12.1 12.11.8 semver Not specified
CNA WatchGuard Fireware OS affected 2025.1 2026.1.2 semver Not specified

References

ReferenceSourceLinkTags
www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00007 5d1c2695-1a31-4499-88ae-e847036fd7e3 www.watchguard.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: btaol (en)

Additional Advisory Data

Exploits

CNA: WatchGuard is not aware of any exploitation of this issue in the wild.

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