CVE-2021-43226

Microsoft Windows Privilege Escalation Vulnerability

Windows Common Log File System Driver Elevation of Privilege Vulnerability

CVSS 7.8 KEVNo patch available

This record: live connection— last retrieved: 8 November 2026 at 08:18.

Vendor

Microsoft

Products

Windows 10, Windows 11, Windows 7, Windows Server

up to version cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x64:*

Published

15 December 2021

Last modified

22 August 2026

Original source information

Taken directly from NVD, CISA or the vendor — sometimes in English, unchanged from the source.

Technical description

Windows Common Log File System Driver Elevation of Privilege Vulnerability

CVSS 3.1 — vector details

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack vector

LOCAL

Privileges required

LOW

User interaction

NONE

Confidentiality

High

Integrity

High

Availability

High

EPSS — Exploit Prediction Scoring System

Probability of exploitation within 30 days

3.3%

Percentile

88e

Source: FIRST.org, updated on 7 November 2026.

Patch information

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

IACS Radar assessment

Our own interpretation and context for the source data above.

IACS Radar assessment

Our own interpretation and context for this vulnerability — not an official source.

IACS Radar priority score

54/ 100

Based on CVSS 7.8, EPSS 3.3%, industrial relevance 30/100; raised due to confirmed active exploitation (KEV).

Combines CVSS, EPSS, KEV status, industrial relevance and exposure relevance — a complement to, not a replacement for, the individual scores below and above.

Conditions for exploitation

•Local or adjacent access to the device is required.
•Limited user privileges are required.
•No user interaction required.

Operational impact & energy relevance

Possible loss of visibility of or control over the process upon successful exploitation.

No strong energy-sector-specific signals recognised; general OT/ICS relevance.

Recommended defensive measures

•Apply the latest firmware or software update and validate its integrity.
•Restrict network access to the affected device to a dedicated OT management segment.
•Implement network segmentation in line with zones and conduits (IEC 62443-3-2).
•Monitor for abnormal protocol traffic using an OT-aware detection system.

Industrial relevance score

30/ 100

• Included in the CISA KEV catalogue: confirmed evidence of actual exploitation.

Classification is provisional; manual verification by an OT security analyst is recommended.

Classified by IACS Radar-analysepijplijn (geautomatiseerd) on 8 November 2026.

IEC 62443 mapping

IEC 62443-4-1FR3 · Systeemintegriteit

Automatic IACS Radar assessment based on the reported CWE weakness classification; not an official certification statement.

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