Common Log File System Driver
CVE-2020-1154 — Windows Common Log File System Driver Elevation of Privilege Vulnerability
Executive Summary
An elevation of privilege vulnerability exists when the Windows Common Log File System (CLFS) driver improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run processes in an elevated context. To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system. The security update addresses the vulnerability by correcting how CLFS handles objects in memory.
Overview
7.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.0
EPSS Score
0.00821
probability of exploitation in the next 30 days
0.5243 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
27 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows 10 for 32-bit Systems | 4556826 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 for x64-based Systems | 4556826 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1607 for 32-bit Systems | 4556813 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1607 for x64-based Systems | 4556813 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1709 for 32-bit Systems | 4556812 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1709 for ARM64-based Systems | 4556812 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1709 for x64-based Systems | 4556812 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1803 for 32-bit Systems | 4556807 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1803 for ARM64-based Systems | 4556807 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1803 for x64-based Systems | 4556807 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1809 for 32-bit Systems | 4551853 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1809 for ARM64-based Systems | 4551853 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1809 for x64-based Systems | 4551853 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1903 for 32-bit Systems | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1903 for ARM64-based Systems | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1903 for x64-based Systems | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1909 for 32-bit Systems | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1909 for ARM64-based Systems | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1909 for x64-based Systems | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 7 for 32-bit Systems Service Pack 1 4556836 (Monthly Rollup) 4556843 (Security Only) Important Elevation of Privilege 4550964 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556836 4556843 Windows 7 for x64-based Systems Service Pack 1 4556836 (Monthly Rollup) 4556843 (Security Only) Important Elevation of Privilege 4550964 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556836 4556843 Windows 8.1 for 32-bit systems 4556846 (Monthly Rollup) 4556853 (Security Only) Important Elevation of Privilege 4550961 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows 8.1 for x64-based systems 4556846 (Monthly Rollup) 4556853 (Security Only) Important Elevation of Privilege 4550961 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows RT 8.1 | 4556846 (Monthly Rollup) |
Important | Elevation of Privilege | Yes |
| Windows Server 2008 for 32-bit Systems Service Pack 2 4556860 (Monthly Rollup) 4556854 (Security Only) Important Elevation of Privilege 4550951 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556860 4556854 Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 4556860 (Monthly Rollup) 4556854 (Security Only) Important Elevation of Privilege 4550951 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556860 4556854 Windows Server 2008 for x64-based Systems Service Pack 2 4556860 (Monthly Rollup) 4556854 (Security Only) Important Elevation of Privilege 4550951 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556860 4556854 Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 4556860 (Monthly Rollup) 4556854 (Security Only) Important Elevation of Privilege 4550951 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556860 4556854 Windows Server 2008 R2 for x64-based Systems Service Pack 1 4556836 (Monthly Rollup) 4556843 (Security Only) Important Elevation of Privilege 4550964 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556836 4556843 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 4556836 (Monthly Rollup) 4556843 (Security Only) Important Elevation of Privilege 4550964 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4556836 4556843 Windows Server 2012 4556840 (Monthly Rollup) 4556852 (Security Only) Important Elevation of Privilege 4550917 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 (Server Core installation) 4556840 (Monthly Rollup) 4556852 (Security Only) Important Elevation of Privilege 4550917 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 4556846 (Monthly Rollup) 4556853 (Security Only) Important Elevation of Privilege 4550961 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 (Server Core installation) 4556846 (Monthly Rollup) 4556853 (Security Only) Important Elevation of Privilege 4550961 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2016 | 4556813 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2016 (Server Core installation) | 4556813 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2019 | 4551853 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2019 (Server Core installation) | 4551853 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server, version 1803 (Server Core Installation) | 4556807 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server, version 1903 (Server Core installation) | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server, version 1909 (Server Core installation) | 4556799 (Security Update) |
Important | Elevation of Privilege | Yes |
Patches
7 patches
| Article | Type | Restart |
|---|---|---|
4556826 |
Security Update | Yes |
4556813 |
Security Update | Yes |
4556812 |
Security Update | Yes |
4556807 |
Security Update | Yes |
4551853 |
Security Update | Yes |
4556799 |
Security Update | Yes |
4556846 |
Monthly Rollup | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
References
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