CVE-2026-4266
Insecure Deserialization in WatchGuard Fireware OS Enables Code Execution
Publication date: 2026-03-30
Last updated on: 2026-03-30
Assigner: WatchGuard Technologies, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| watchguard | fireware_os | From 12.1 (inc) to 12.11.8 (inc) |
| watchguard | fireware_os | From 2025.1 (inc) to 2026.1.2 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-502 | The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. |
Attack-Flow Graph
AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability allows an attacker with prior write access to execute arbitrary code with high privileges, potentially compromising confidentiality, integrity, and availability of the system.
Such a compromise could lead to unauthorized access or manipulation of sensitive data, which may negatively impact compliance with standards and regulations like GDPR and HIPAA that require protection of personal and health information.
However, the provided information does not explicitly state the direct effects on compliance with these regulations.
Can you explain this vulnerability to me?
CVE-2026-4266 is an Insecure Deserialization vulnerability found in the WatchGuard Fireware OS Access Portal. It allows an attacker who already has write access to the local filesystem—obtained through another vulnerability—to execute arbitrary code with the privileges of the 'portald' user.
This vulnerability affects Fireware OS versions 12.1 through 12.11.8 and 2025.1 through 2026.1.2, but does not affect Firebox platforms that do not support the Access Portal feature, such as the T-15 and T-35 models.
How can this vulnerability impact me? :
If exploited, this vulnerability allows an attacker to execute arbitrary code with high privileges (the 'portald' user) on the affected system. This can lead to unauthorized control over the device, potentially compromising confidentiality, integrity, and availability of the system.
Since the attacker must already have write access to the local filesystem through another vulnerability, this issue can be part of a chained attack, increasing the overall risk to the system.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
There is no specific information provided about detection methods or commands to identify this vulnerability on your network or system.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability has been resolved in Fireware OS versions 12.12 and 2026.2.
Since there is no available workaround, the immediate step to mitigate this vulnerability is to upgrade affected Fireware OS versions (12.1 through 12.11.8 and 2025.1 through 2026.1.2) to version 12.12 or 2026.2.