CVE-2026-4266 json
WatchGuard Firebox Insecure Deserialization in Fireware Access Portal
published 2026-03-30 7 mo ago modified 2026-08-28 2 mo ago also EUVD-2026-17079
- cvss
- 6.7
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 20%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- WatchGuard Fireware OS 12.11.9, 12.12, 2026.2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 7 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.4 | 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 |
| CNA | 4.0 | 8.4 | 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 |
| NVD | 3.1 | 6.7 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
Affected products
- WatchGuard Fireware OS
Classification
- Weakness
-
- CWE-502 Deserialization of Untrusted Data
References
-
psirt.watchguard.com
/CVE-2026-4266
vendor-advisory, broken-link
-
watchguard.com
/wgrd-psirt/advisory/wgsa-2026-00007
vendor-advisory
Sources
- CVE List CVE-2026-4266
- NVD CVE-2026-4266
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