Overview
Microsoft Windows Common Log File System Driver contains a privilege escalation vulnerability that could allow a local, privileged attacker to bypass certain security mechanisms.
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43226 ; https://nvd.nist.gov/vuln/detail/CVE-2021-43226
Key Details
| Property | Value |
|---|---|
| CVE ID | CVE-2021-43226 |
| Vendor / Product | Microsoft — Windows |
| NVD Published | 2021-12-15 |
| NVD Last Modified | 2025-10-30 |
| CVSS 3.1 Score | 7.8 |
| CVSS 3.1 Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Severity | HIGH |
| CISA KEV Added | 2025-10-06 |
| CISA KEV Deadline | 2025-10-27 |
| Known Ransomware Use | No |
CVSS 3.1 Breakdown
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Required Action
CISA BOD 22-01 Deadline: 2025-10-27.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Timeline
| Date | Event |
|---|---|
| 2025-10-06 | Added to CISA Known Exploited Vulnerabilities catalog |
| 2025-10-27 | CISA BOD 22-01 remediation deadline |
References
| Resource | Type |
|---|---|
| NVD — CVE-2021-43226 | Vulnerability Database |
| CISA KEV Catalog Entry | US Government |