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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 2 May 2023. Known ransomware use
Windows 10 1507Operating system · Microsoft

CVE-2023-28252

HIGH · 7.8 CVSS v3.1 Published 2023-04-11
Fix available
A fix is available. Upgrade to 10.0.10240.19869 / 10.0.14393.5850 or later.
See remediation →
96/100
Remediation priority · Urgent
In the wild Ransomware Public exploit Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Windows Common Log File System Driver Elevation of Privilege Vulnerability

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is a privilege escalation vulnerability in the Windows Common Log File System (CLFS) driver (clfs.sys), a kernel-mode logging infrastructure used by Windows components and applications. The vulnerability allows a local attacker to elevate from a low-privileged account to SYSTEM privileges by exploiting improper handling of log file operations in the CLFS driver.

MitigationApply the Microsoft security update for CVE-2023-28252, which patches the CLFS driver vulnerability. Organizations should prioritize patching affected Windows systems given the high-severity rating and public disclosure of exploitation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows 10 1507Operating system
Affected:< 10.0.10240.19869
Windows 10 1607Operating system
Affected:< 10.0.14393.5850
Windows 10 1809Operating system
Affected:< 10.0.17763.4252
Windows 10 20h2Operating system
Affected:< 10.0.19042.2846
Windows 10 21h2Operating system
Affected:< 10.0.19044.2846
Windows 10 22h2Operating system
Affected:< 10.0.19045.2846
Windows 11 21h2Operating system
Affected:< 10.0.22000.1817
Windows 11 22h2Operating system
Affected:< 10.0.22621.1555

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Windows version and build number
    Run 'winver' from the Run dialog, or execute 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' in Command Prompt, or use 'Get-ComputerInfo | Select-Object WindowsProductName, WindowsVersion, OsHardwareAbstractionLayer' in PowerShell
    Affected if The Windows build number falls below the version thresholds listed for any affected Windows 10 or Windows 11 release (1507, 1607, 1809, 20h2, 21h2, 22h2, 11-21h2, 11-22h2)
  2. Confirm CLFS.sys driver is present
    Verify that C:\Windows\System32\drivers\CLFS.sys exists on the system using 'Test-Path C:\Windows\System32\drivers\CLFS.sys' in PowerShell or checking via File Explorer
    Affected if The CLFS.sys driver file exists on the system (this is a default component in affected Windows versions)
  3. Retrieve CLFS.sys file version
    Run 'Get-Item C:\Windows\System32\drivers\CLFS.sys | Select-Object VersionInfo' in PowerShell, or right-click the file in File Explorer, select Properties, and view the Details tab
    Affected if The CLFS.sys file version is below the corresponding threshold for your Windows build (comparing to 10.0.10240.19869, 10.0.14393.5850, 10.0.17763.4252, 10.0.19042.2846, 10.0.19044.2846, 10.0.19045.2846, 10.0.22000.1817, or 10.0.22621.1555 depending on your Windows version)
  4. Check for recent security updates
    Run 'Get-HotFix | Where-Object {$_.Description -eq "Security Update"} | Sort-Object InstalledOn -Descending | Select-Object -First 10' in PowerShell to list recently installed security updates, or view the Windows Update history in Settings > Windows Update > Update history
    Affected if No security update corresponding to CVE-2023-28252 appears in the installed updates list and the Windows version/build is below the fixed thresholds

If your Windows build number is below the affected thresholds AND the CLFS.sys driver is present AND no CVE-2023-28252 security update is installed, your environment is vulnerable to elevation of privilege via this flaw.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.0.10240.19869 / 10.0.14393.5850 / 10.0.17763.4252 or later
Fixed in 10.0.10240.1986910.0.14393.585010.0.17763.4252
Vendor patch msrc.microsoft.com →
Interim mitigation

Apply the Microsoft security update for CVE-2023-28252, which patches the CLFS driver vulnerability. Organizations should prioritize patching affected Windows systems given the high-severity rating and public disclosure of exploitation.

Recommended fix High confidence

Install the April 2023 or later Windows Security Update (KB5023698 for Win10, KB5023696 for Win11) specific to your Windows version

  1. 1. Identify the exact Windows version by running 'winver' or 'systeminfo' in Command Prompt
  2. 2. Determine which patch tier your version falls into based on the affected versions list
  3. 3. Open Windows Update by navigating to Settings > Update & Security > Windows Update
  4. 4. Click 'Check for updates' to download and install the latest cumulative security update
  5. 5. Alternatively, manually download the appropriate security update from the Microsoft Update Catalog for your specific Windows version (KB5023698 or later for Windows 10; KB5023696 or later for Windows 11)
  6. 6. After installation, restart the system when prompted
  7. 7. Verify the fix by confirming the build number matches or exceeds the fixed version for your tier (e.g., 10.0.19045.2846 for Windows 10 22h2)
Caveat Standard Windows security update - minimal risk; may require restart

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1507 Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-28252 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-28252 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data