WatchGuard Firebox Insecure Deserialization in Fireware Access Portal
Summary
| CVE | CVE-2026-4266 |
|---|---|
| State | PUBLISHED |
| Assigner | WatchGuard |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-30 13:16:22 UTC |
| Updated | 2026-08-14 13:38:15 UTC |
| 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. |
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: 0.002840000 probability, percentile 0.207030000 (date 2026-08-11)
Problem Types: CWE-502 | CWE-502 CWE-502
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 5d1c2695-1a31-4499-88ae-e847036fd7e3 | Secondary | 8.4 | HIGH | 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/C... |
| 4.0 | CNA | DECLARED | 8.4 | HIGH | 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 |
| 3.1 | [email protected] | Primary | 6.7 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
CVSS v4.0 Breakdown
Attack Vector
LocalAttack Complexity
LowAttack Requirements
NonePrivileges Required
HighUser Interaction
NoneConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
HighUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Hardware | Watchguard | Firebox M295 | - | All | All | All |
| Hardware | Watchguard | Firebox M395 | - | All | All | All |
| Hardware | Watchguard | Firebox M495 | - | All | All | All |
| Hardware | Watchguard | Firebox M595 | - | All | All | All |
| Hardware | Watchguard | Firebox M695 | - | All | All | All |
| Hardware | Watchguard | Firebox T115-w | - | All | All | All |
| Hardware | Watchguard | Firebox T125 | - | All | All | All |
| Hardware | Watchguard | Firebox T125-w | - | All | All | All |
| Hardware | Watchguard | Firebox T145 | - | All | All | All |
| Hardware | Watchguard | Firebox T145-w | - | All | All | All |
| Hardware | Watchguard | Firebox T185 | - | All | All | All |
| Operating System | Watchguard | Fireware | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | WatchGuard | Fireware OS | affected 2025.1 2026.2 custom | Default |
| CNA | WatchGuard | Fireware OS | affected 12.1 12.12 custom | Default |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| psirt.watchguard.com/CVE-2026-4266 | 5d1c2695-1a31-4499-88ae-e847036fd7e3 | psirt.watchguard.com | Broken Link |
| www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00007 | 5d1c2695-1a31-4499-88ae-e847036fd7e3 | www.watchguard.com | Vendor Advisory |
| 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
Solutions
CNA: Fireware OS 2026.2, Fireware OS 12.12
Exploits
CNA: WatchGuard is not aware of any exploitation of this issue in the wild.
There are currently no legacy QID mappings associated with this CVE.