What is the CVSS score of EUVD-2026-12166?

EUVD-2026-12166 has a CVSS 3.0 base score of 8.8 (High). CVSS vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 1.6%.

Which versions of PHP are affected by EUVD-2026-12166?

CVE-2026-3838 is a high-severity vulnerability affecting all Unraid versions that permits authenticated users to execute arbitrary code with root privileges.

How to fix or mitigate EUVD-2026-12166?

Within 24 hours: Identify and inventory all Unraid instances in your environment and restrict network access to update.php to essential administrators only. Within 7 days: Implement network segmentation to isolate Unraid systems and deploy WAF rules blocking POST requests to update.php from untrusted sources; evaluate whether Unraid is critical to operations. Within 30 days: Contact Unraid for patch availability; if unavailable, prepare migration plan to alternative solutions or maintain air-gapped deployment with strict access controls pending vendor remediation.

PHP EUVD-2026-12166

| CVE-2026-3838 HIGH

Path Traversal (CWE-22)

2026-03-13 zdi

PHP Path Traversal RCE Unraid

8.8

CVSS 3.0 · NVD

Severity by source

NVD PRIMARY

8.8 HIGH

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

EUVD ID Assigned

Mar 13, 2026 - 21:01 euvd

EUVD-2026-12166

Analysis Generated

Mar 13, 2026 - 21:01 vuln.today

CVE Published

Mar 13, 2026 - 20:37 nvd

HIGH 8.8

DescriptionCVE.org

Unraid Update Request Path Traversal Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Unraid. Authentication is required to exploit this vulnerability.

The specific flaw exists within the update.php file. The issue results from the lack of proper validation of a user-supplied path prior to using it in file operations. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-28951.

AnalysisAI

Critical path traversal vulnerability in Unraid's update.php file that allows authenticated remote attackers to execute arbitrary code as root. The vulnerability affects all versions of Unraid (per CPE data) and was discovered by Zero Day Initiative (ZDI-CAN-28951). With a CVSS score of 8.8 and requiring only low privileges, this represents a severe risk for Unraid installations.

Technical ContextAI

The vulnerability exists in the update.php file within Unraid (CPE: cpe:2.3:a:unraid:unraid:*:*:*:*:*:*:*:*), a popular NAS operating system. As a CWE-22 (Path Traversal) vulnerability, the flaw stems from insufficient validation of user-supplied file paths, allowing attackers to traverse directories and access files outside the intended directory structure. In PHP applications like Unraid, path traversal can be particularly dangerous as it may allow writing to sensitive system files or executing arbitrary code through PHP's file inclusion mechanisms.

RemediationAI

No specific patch information is available in the provided data. The Zero Day Initiative advisory (https://www.zerodayinitiative.com/advisories/ZDI-26-171/) should be consulted for vendor response and patch availability. In the absence of a patch, consider these mitigations: 1) Restrict access to the Unraid web interface to trusted networks only, 2) Implement strong authentication and monitor for suspicious account activity, 3) Disable or restrict access to update.php if updates can be managed through alternative means, 4) Monitor file system activity for unexpected modifications in system directories.