OnlyPatch
Windows Common Log File System Driver

CVE-2025-32713 — Windows Common Log File System Driver Elevation of Privilege Vulnerability

Important CVSS 7.8 EPSS 0.00704 🔬 Patch diffed 2025-06 archive

Executive Summary

Heap-based buffer overflow in Windows Common Log File System Driver allows an authorized attacker to elevate privileges locally.

Overview

7.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
Category Elevation of Privilege
Weakness CWE-122: Heap-based Buffer Overflow
Released Jun 10 2025
Last Updated Jun 10 2025
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00704 — 0.50179 percentile
NVD CVSS 7.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/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
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 6.8

EPSS Score

0.00704
probability of exploitation in the next 30 days
0.50179 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

25 affected products
Product KB Article Severity Impact Restart Required
Windows 10 for 32-bit Systems 5060998 (Security Update) Important Elevation of Privilege Yes
Windows 10 for x64-based Systems 5060998 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1607 for 32-bit Systems 5061010 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1607 for x64-based Systems 5061010 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for 32-bit Systems 5060531 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for x64-based Systems 5060531 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for 32-bit Systems 5060533 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for ARM64-based Systems 5060533 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for x64-based Systems 5060533 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for 32-bit Systems 5060533 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for ARM64-based Systems 5060533 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for x64-based Systems 5060533 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 22H2 for ARM64-based Systems 5060999 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 22H2 for x64-based Systems 5060999 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 23H2 for ARM64-based Systems 5060999 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 23H2 for x64-based Systems 5060999 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 24H2 for ARM64-based Systems 5060842 (Security Update) 5060841 (SecurityHotpatchUpdate) Important Elevation of Privilege 5058411 5058497 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.4349 10.0.26100.4270 Yes None Windows 11 Version 24H2 for x64-based Systems 5060842 (Security Update) 5060841 (SecurityHotpatchUpdate) Important Elevation of Privilege 5058411 5058497 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.4349 10.0.26100.4270 Yes None Windows Server 2008 for 32-bit Systems Service Pack 2 5061026 (Monthly Rollup) 5061072 (Security Only) Important Elevation of Privilege 5058449 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.23351 Yes None Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 5061026 (Monthly Rollup) 5061072 (Security Only) Important Elevation of Privilege 5058449 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.23351 Yes None Windows Server 2008 for x64-based Systems Service Pack 2 5061026 (Monthly Rollup) 5061072 (Security Only) Important Elevation of Privilege 5058449 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.23351 Yes None Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 5061026 (Monthly Rollup) 5061072 (Security Only) Important Elevation of Privilege 5058449 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.23351 Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 5061078 (Monthly Rollup) 5061036 (Security Only) Important Elevation of Privilege 5058430 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.1.7601.27769 Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 5061078 (Monthly Rollup) 5061036 (Security Only) Important Elevation of Privilege 5058430 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.1.7601.27769 Yes None Windows Server 2012 5061059 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2012 (Server Core installation) 5061059 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2012 R2 5061018 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2012 R2 (Server Core installation) 5061018 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2016 5061010 (Security Update) Important Elevation of Privilege Yes
Windows Server 2016 (Server Core installation) 5061010 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 5060531 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 (Server Core installation) 5060531 (Security Update) Important Elevation of Privilege Yes
Windows Server 2022 5060526 (Security Update) 5060525 (SecurityHotpatchUpdate) Important Elevation of Privilege 5058385 5058500 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.3807 10.0.20348.3745 Yes None Windows Server 2022 (Server Core installation) 5060526 (Security Update) 5060525 (SecurityHotpatchUpdate) Important Elevation of Privilege 5058385 5058500 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.3807 10.0.20348.3745 Yes None Windows Server 2022, 23H2 Edition (Server Core installation) 5060118 (Security Update) Important Elevation of Privilege Yes

Patches

8 patches
Article Type Restart
5060998 Security Update Yes
5061010 Security Update Yes
5060531 Security Update Yes
5060533 Security Update Yes
5060999 Security Update Yes
5061059 Monthly Rollup Yes
5061018 Monthly Rollup Yes
5060118 Security Update Yes

Patch Diff

ghidriff · clfs.sys (KB5060842)

Missing validation of the log sector size in clfs.sys CClfsLogFcbPhysical::ReadLogBlock. The value is read from the log's device/container context at (this+0x2c8)+0x90 and used in the read-buffer sizing and alignment arithmetic. The patch adds an up-front check that it is non-zero, at most 0x1000, 512-aligned and an exact divisor of a page - admitting only 0x200/0x400/0x800/0x1000. Gated behind Feature_3984600376; the unchecked path still ships and runs when the flag is disabled. Note this is the first of three separate ReadLogBlock fixes (2025-06, 2026-05 Server Feature_748929339, 2026-08 Feature_344697147) - three distinct defects, not a variant chain.

Pre-patch version 10.0.26100.4061
Post-patch version 10.0.26100.4343
Function Address Change Note
CClfsLogFcbPhysical::ReadLogBlock code (sector-size validation added, gated on Feature_3984600376) The patch adds an up-front sanity check on the sector size read from the log's device/container context (`*(uint *)(*(longlong *)(this + 0x2c8) + 0x90)`): it must satisfy `size - 1 < 0x1000`, `(size & 0x1ff) == 0` and `0x1000 % size == 0` - i.e. one of 0x200 / 0x400 / 0x800 / 0x1000. Pre-patch the value flowed into the read-buffer arithmetic unchecked. The rest of the function is register-allocation churn from the added block.
Feature_3984600376__private_IsEnabledDeviceUsageNoInline / _IsEnabledFallback added -- CFR gate Both paths ship in 10.0.26100.4343.
View full diff report View RCA report

Attack Path

Unvalidated sector size drives the read-buffer arithmetic in ReadLogBlock

Attack path for CVE-2025-32713 Unvalidated sector size drives the read-buffer arithmetic in ReadLogBlock 01 — ENTRY Standard user creates a CLFS log and triggers a block read CreateLogFile then any operation that reads a log block. Unprivileged; CLFS is always present. 02 — CONTROLLED INPUT The sector size comes from the log's own device/container context Reached as *(uint *)(*(longlong *)(this + 0x2c8) + 0x90) - metadata the attacker influences through the log file. 03 — PATH ReadLogBlock sizes and aligns its read buffer from that value The sector size participates in the buffer allocation and the block-copy arithmetic that follows. 04 — MISSING CHECK No sanity check on the sector size before it is used The patch adds: `size - 1 < 0x1000` (non-zero, at most one page), `(size & 0x1ff) == 0` (512-aligned), and `0x1000 % size == 0` (divides a page evenly) - admitting only 0x200, 0x400, 0x800, 0x1000. A value outside that set makes the downstream sizing and alignment arithmetic wrong. 05 — PRIMITIVE Malformed sector size produces incorrect buffer sizing in the block-read path MSRC rates this Elevation of Privilege. Gated behind Feature_3984600376; the unchecked path still ships.

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

Known Exploits

Acknowledgments

Seunghoe Kim with S2W Inc.

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