OnlyPatch
Windows Common Log File System Driver

CVE-2021-43224 — Windows Common Log File System Driver Information Disclosure Vulnerability

Important CVSS 5.5 EPSS 0.03872 🔬 Patch diffed 2021-12 archive

Executive Summary

None

Overview

5.5
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Information Disclosure
Released Dec 14 2021
Last Updated Dec 14 2021
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.03872 — 0.89105 percentile
NVD CVSS 5.5 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
None
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 4.8

EPSS Score

0.03872
probability of exploitation in the next 30 days
0.89105 percentile - updated 2026-07-25
View on FIRST.org

Affected Products

32 affected products
Product KB Article Severity Impact Restart Required
Windows 10 for 32-bit Systems 5008230 (Security Update) Important Information Disclosure Yes
Windows 10 for x64-based Systems 5008230 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1607 for 32-bit Systems 5008207 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1607 for x64-based Systems 5008207 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1809 for 32-bit Systems 5008218 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1809 for ARM64-based Systems 5008218 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1809 for x64-based Systems 5008218 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1909 for 32-bit Systems 5008206 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1909 for ARM64-based Systems 5008206 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1909 for x64-based Systems 5008206 (Security Update) Important Information Disclosure Yes
Windows 10 Version 2004 for 32-bit Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 2004 for ARM64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 2004 for x64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 20H2 for 32-bit Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 20H2 for ARM64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H1 for 32-bit Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H1 for ARM64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H1 for x64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H2 for 32-bit Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H2 for ARM64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H2 for x64-based Systems 5008212 (Security Update) Important Information Disclosure Yes
Windows 11 version 21H2 for ARM64-based Systems 5008215 (Security Update) Important Information Disclosure Yes
Windows 11 version 21H2 for x64-based Systems 5008215 (Security Update) Important Information Disclosure Yes
Windows 7 for 32-bit Systems Service Pack 1 5008244 (Monthly Rollup) 5008282 (Security Only) Important Information Disclosure 5007236 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.1.7601.25796 Yes 5008244 5008282 Windows 7 for x64-based Systems Service Pack 1 5008244 (Monthly Rollup) 5008282 (Security Only) Important Information Disclosure 5007236 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.1.7601.25796 Yes 5008244 5008282 Windows 8.1 for 32-bit systems 5008263 (Monthly Rollup) 5008285 (Security Only) Important Information Disclosure 5007247 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.3.9600.20207 Yes 5008263 5008285 Windows 8.1 for x64-based systems 5008263 (Monthly Rollup) 5008285 (Security Only) Important Information Disclosure 5007247 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.3.9600.20207 Yes 5008263 5008285 Windows RT 8.1 5008263 (Monthly Rollup) Important Information Disclosure Yes
Windows Server 2008 for 32-bit Systems Service Pack 2 5008274 (Monthly Rollup) 5008271 (Security Only) Important Information Disclosure 5007263 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.0.6003.21309 Yes 5008274 5008271 Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 5008274 (Monthly Rollup) 5008271 (Security Only) Important Information Disclosure 5007263 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.0.6003.21309 Yes 5008274 5008271 Windows Server 2008 for x64-based Systems Service Pack 2 5008274 (Monthly Rollup) 5008271 (Security Only) Important Information Disclosure 5007263 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.0.6003.21309 Yes 5008274 5008271 Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 5008274 (Monthly Rollup) 5008271 (Security Only) Important Information Disclosure 5007263 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.0.6003.21309 Yes 5008274 5008271 Windows Server 2008 R2 for x64-based Systems Service Pack 1 5008244 (Monthly Rollup) 5008282 (Security Only) Important Information Disclosure 5007236 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.1.7601.25796 Yes 5008244 5008282 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 5008244 (Monthly Rollup) 5008282 (Security Only) Important Information Disclosure 5007236 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.1.7601.25796 Yes 5008244 5008282 Windows Server 2012 5008277 (Monthly Rollup) 5008255 (Security Only) Important Information Disclosure 5007260 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.2.9200.23545 6.2.9200.23540 Yes 5008277 5008255 Windows Server 2012 (Server Core installation) 5008277 (Monthly Rollup) 5008255 (Security Only) Important Information Disclosure 5007260 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.2.9200.23545 6.2.9200.23540 Yes 5008277 5008255 Windows Server 2012 R2 5008263 (Monthly Rollup) 5008285 (Security Only) Important Information Disclosure 5007247 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.3.9600.20207 Yes 5008263 5008285 Windows Server 2012 R2 (Server Core installation) 5008263 (Monthly Rollup) 5008285 (Security Only) Important Information Disclosure 5007247 Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C 6.3.9600.20207 Yes 5008263 5008285 Windows Server 2016 5008207 (Security Update) Important Information Disclosure Yes
Windows Server 2016 (Server Core installation) 5008207 (Security Update) Important Information Disclosure Yes
Windows Server 2019 5008218 (Security Update) Important Information Disclosure Yes
Windows Server 2019 (Server Core installation) 5008218 (Security Update) Important Information Disclosure Yes
Windows Server 2022 5008223 (Security Update) Important Information Disclosure Yes
Windows Server 2022 (Server Core installation) 5008223 (Security Update) Important Information Disclosure Yes
Windows Server, version 2004 (Server Core installation) 5008212 (Security Update) Important Information Disclosure Yes
Windows Server, version 20H2 (Server Core Installation) 5008212 (Security Update) Important Information Disclosure Yes

Patches

8 patches
Article Type Restart
5008230 Security Update Yes
5008207 Security Update Yes
5008218 Security Update Yes
5008206 Security Update Yes
5008212 Security Update Yes
5008215 Security Update Yes
5008263 Monthly Rollup Yes
5008223 Security Update Yes

Patch Diff

ghidriff · clfs.sys (KB5008215)

Patch diff 10.0.22000.258 -> 10.0.22000.376 (clfs; heavy LoadContainerQ/FindSymbol rewrites)

Pre-patch version 10.0.22000.258
Post-patch version 10.0.22000.376
Function Address Change Note
CClfsLogFcbVirtual::Open 1c0041408 -> 1c0041510 code, length, address, called similarity 0.99
_guard_dispatch_icall 1c000cc10 refcount, calling similarity 1.0
CClfsBaseFile::GetBaseLogRecord 1c002c980 -> 1c002ca68 refcount, address, calling similarity 1.0
memcpy 1c000cc40 refcount similarity 1.0
CClfsBaseFile::GetSymbol 1c002c788 -> 1c002c858 code, length, address similarity 0.96
CClfsBaseFile::GetSymbol 1c002bca0 -> 1c002bd60 code, length, address similarity 0.8
CClfsLogFcbVirtual::QueryLogFileInfo 1c0040d90 -> 1c0040e00 code, length, address similarity 0.71
`CClfsBaseFilePersisted::LoadContainerQ'::__l1::fin$0 1c0046660 -> 1c0046770 code, length, address, called similarity 0.71
CClfsBaseFile::FindSymbol 1c004118c -> 1c00411fc code, refcount, length, address, called similarity 0.36
CClfsBaseFilePersisted::LoadContainerQ 1c0035450 -> 1c0035540 code, refcount, length, address, calling, called similarity 0.09
memset 1c000cf00 refcount, calling similarity 1.0
NTOSKRNL.EXE::ExAllocatePoolWithTag EXTERNAL:00000001 refcount similarity 1.0
NTOSKRNL.EXE::ExFreePoolWithTag EXTERNAL:00000002 refcount, calling similarity 1.0
CClfsBaseFile::AddrToOffset 1c002c980 -> 1c0029c88 code, name, fullname, refcount, length, sig, address, calling, called similarity 0.3
View full diff report View RCA report Download PoC

Known Exploits

Acknowledgments

Anonymous
HyungSeok Han

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