dbcve.org
Windows 10 1809Operating system · Microsoft

CVE-2025-50170

HIGH · 7.8 CVSS v3.1 Published 2025-08-12
Fix available
A fix is available. Upgrade to 10.0.17763.7678 / 10.0.19044.6216 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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
Improper handling of insufficient permissions or privileges in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.

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 local privilege escalation vulnerability in the Windows Cloud Files Mini Filter Driver. The driver fails to properly validate or handle permission checks, allowing an authorized local attacker with low privileges to elevate to higher system privileges through improper handling of insufficient permissions.

MitigationApply the Microsoft security update for CVE-2025-50170 through Windows Update or enterprise patch management to remediate the privilege escalation in the Cloud Files Mini Filter Driver.

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 1809Operating system
Affected:< 10.0.17763.7678
Windows 10 21h2Operating system
Affected:< 10.0.19044.6216
Windows 10 22h2Operating system
Affected:< 10.0.19045.6216
Windows 11 22h2Operating system
Affected:< 10.0.22621.5768
Windows 11 23h2Operating system
Affected:< 10.0.22631.5768
Windows 11 24h2Operating system
Affected:< 10.0.26100.4851
Windows Server 2019Operating system
Affected:< 10.0.17763.7678
Windows Server 2022Operating system
Affected:< 10.0.20348.3989

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. Check Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify your Windows version and build number
    Affected if The build number is lower than the affected version for your Windows release (e.g., below 17763.7678 for Windows 10 1809/Server 2019, below 19044.6216 for Windows 10 21h2, etc.)
  2. Locate the Cloud Files Mini Filter Driver
    Search for fc.sys in %SystemRoot%\System32\drivers\ or run 'driverquery /v | findstr -i fc' to list the driver
    Affected if The driver file fc.sys exists on the system (the vulnerability applies whenever this driver is present and loaded)
  3. Check if the driver is loaded
    Run 'fltmc filters' or check in PowerShell: 'Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\fc" -ErrorAction SilentlyContinue'
    Affected if The Cloud Files Mini Filter Driver service (fc) is present and active in the filter driver list
  4. Verify driver file version
    Right-click fc.sys in System32\drivers\, go to Properties > Details, or run 'powershell (Get-Item "C:\Windows\System32\drivers\fc.sys").VersionInfo'
    Affected if The file version is lower than the patched version corresponding to your Windows build, or if you cannot determine the version and your Windows build falls within the affected range

You are affected if your Windows build number falls within the vulnerable version ranges AND the Cloud Files Mini Filter Driver (fc.sys) is present on your system.

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 10.0.17763.7678 / 10.0.19044.6216 / 10.0.19045.6216 or later
Fixed in 10.0.17763.767810.0.19044.621610.0.19045.6216
Interim mitigation

Apply the Microsoft security update for CVE-2025-50170 through Windows Update or enterprise patch management to remediate the privilege escalation in the Cloud Files Mini Filter Driver.

Recommended fix High confidence

Apply the Microsoft security update for CVE-2025-50170 to reach the fixed build numbers: Windows 10 1809: 10.0.17763.7678 | Windows 10 21h2: 10.0.19044.6216 | Windows 10 22h2: 10.0.19045.6216 | Windows 11 22h2: 10.0.22621.5768 | Windows 11 23h2: 10.0.22631.5768 | Windows 11 24h2: 10.0.26100.4851 | W

  1. Identify the Windows version and build number by running 'winver' or 'systeminfo'
  2. Open Settings > Windows Update and check for available updates
  3. Alternatively, manually download the security update for this CVE from the Microsoft Update Catalog (search for CVE-2025-50170 or KB reference from Microsoft Security Response Center)
  4. Install the relevant Windows security update for your version (e.g., KB5063206 for Windows 10 22h2, KB5063190 for Windows 11 23h2)
  5. Restart the system when prompted to complete the installation
  6. Verify the patch was installed by checking Windows Update history or running 'systeminfo' to confirm the new build number matches or exceeds the fixed version for your Windows release
Caveat Standard Windows security update; no breaking changes expected for this privilege escalation patch

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

Fix this in Windows 10 1809 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,744.

Scan for this in your stack

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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-2025-50170 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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