CVE-2026-4266
Medium
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.
SeverityMedium
CVSS6.7
Exploit probability—
ProductWatchguard Fireware
PublishedMar 30, 2026
First seenMar 30, 2026
Weakness typeCWE-502Deserialization of untrusted data
How to fix
Update
- watchguard fireware2026.2, 12.12 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| watchguard fireware | 2025.1 ≤ v < 2026.2, 12.1 ≤ v < 12.12 | 2026.2, 12.12 |
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