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Windows 10 1809Operating system · Microsoft

CVE-2026-50401

MEDIUM · 5.5 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 10.0.17763.9020 / 10.0.19044.7548 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click 5 weeks old

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
Out-of-bounds read in Windows Cloud Files Mini Filter Driver allows an authorized attacker to disclose information locally.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 1mo ago

Surfaced from public web coverage — external links open in a new tab.

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

An out-of-bounds read vulnerability exists in the Windows Cloud Files Mini Filter Driver, a kernel-mode component responsible for managing cloud file storage operations. The vulnerability allows a locally authenticated attacker to read memory contents beyond the intended buffer boundaries, potentially exposing sensitive kernel or heap memory data.

MitigationApply the Microsoft security update for this vulnerability through standard Windows Update or patch management processes. Until the patch is available, limit local privileged access and monitor for indicators of compromise related to memory disclosure techniques.

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:< 10.0.17763.9020
Windows 10 21h2Operating system
Affected:< 10.0.19044.7548
Windows 10 22h2Operating system
Affected:< 10.0.19045.7548
Windows 11 24h2Operating system
Affected:< 10.0.26100.8875
Windows 11 25h2Operating system
Affected:< 10.0.26200.8875
Windows 11 26h1Operating system
Affected:< 10.0.28000.2269< 10.0.28000.2525
Windows Server 2019Operating system
Affected:< 10.0.17763.9020
Windows Server 2022Operating system
Affected:< 10.0.20348.5386

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
None
Availability
None

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

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 build version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get the Windows build number. Alternatively, run 'ver' at command prompt.
    Affected if The build number is lower than any of the following: 17763.9020 (Windows 10 1809/Server 2019), 19044.7548 (Windows 10 21h2), 19045.7548 (Windows 10 22h2), 20348.5386 (Windows Server 2022), 26100.8875 (Windows 11 24h2), 26200.8875 (Windows 11 25h2), or 28000.2525/28000.2269 (Windows 11 26h1).
  2. Verify Cloud Files Mini Filter Driver is present
    Check for the presence of the driver file 'cldflt.sys' in the system32\drivers folder or by running 'sc query cldflt' at an elevated command prompt.
    Affected if The driver is present on the system, indicating the vulnerable component is installed.
  3. Retrieve Cloud Files Mini Filter Driver version
    Run 'powershell "(Get-Item C:\Windows\System32\drivers\cldflt.sys).VersionInfo.FileVersion"' or right-click the cldflt.sys file, select Properties, and view the Details tab.
    Affected if The driver version number is lower than the fixed version for your specific Windows build (check against the version ranges in the CVE).

You are affected if your Windows build version is lower than the fixed versions listed AND the Cloud Files Mini Filter Driver (cldflt.sys) is installed 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 10.0.17763.9020 / 10.0.19044.7548 / 10.0.19045.7548 or later
Fixed in 10.0.17763.902010.0.19044.754810.0.19045.7548
Interim mitigation

Apply the Microsoft security update for this vulnerability through standard Windows Update or patch management processes. Until the patch is available, limit local privileged access and monitor for indicators of compromise related to memory disclosure techniques.

Recommended fix High confidence

Windows 10 1809: 10.0.17763.9020 | Windows 10 21h2: 10.0.19044.7548 | Windows 10 22h2: 10.0.19045.7548 | Windows 11 24h2: 10.0.26100.8875 | Windows 11 25h2: 10.0.26200.8875 | Windows 11 26h1: 10.0.28000.2525 | Windows Server 2019: 10.0.17763.9020 | Windows Server 2022: 10.0.20348.5386

  1. Run 'winver' or 'systeminfo' to identify the current Windows build version
  2. Open Settings > Windows Update and check for available security updates
  3. Install the latest Windows cumulative security update that addresses this vulnerability
  4. Restart the system when prompted to complete the installation
  5. Verify the fix by running 'winver' and confirming the build number meets or exceeds the minimum fixed version for your Windows release
Caveat Standard Windows security update; no breaking changes expected for typical configurations

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
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

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-2026-50401 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