dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-50309

HIGH · 7.8 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 10.0.14393.9339 / 10.0.17763.9020 or later.
See remediation →
80/100
Remediation priority · High
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
Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code 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

A heap-based buffer overflow vulnerability exists in the Windows NTFS file system driver. By triggering the overflow through a specially crafted operation, a local authenticated attacker can corrupt heap memory and achieve arbitrary code execution with elevated privileges.

MitigationApply the relevant Microsoft Windows security update for NTFS once released. Prior to patching, restrict local administrative privileges and monitor for indicators of compromise involving unusual NTFS driver behavior.

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 1607Operating system
Affected:< 10.0.14393.9339
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 2012Operating system
Affected:all versions= r2

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 installed Windows version
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the Windows build number
    Affected if The build number is less than any of these thresholds: 14393.9339 (1607), 17763.9020 (1809), 19044.7548 (21h2), 19045.7548 (22h2), 26100.8875 (24h2), 26200.8875 (25h2), 28000.2269 or 28000.2525 (26h1); or if running Windows Server 2012 / R2 (all versions)
  2. Verify NTFS driver file version
    Run 'Get-ItemProperty C:\Windows\System32\ntfs.sys' in PowerShell and note the PSChildName or FileVersion attribute
    Affected if The driver version is below the corresponding Windows version fix threshold listed above or the file is unversioned on Windows Server 2012/R2
  3. Confirm Windows Server 2012/R2 status
    Run 'systeminfo | findstr "Server"' to check if the OS is Windows Server 2012 or Server 2012 R2
    Affected if The system is Windows Server 2012 or Windows Server 2012 R2 (any version, as all versions are affected)
  4. Check for applied security updates
    Run 'Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 20' to list recently installed patches
    Affected if No recent NTFS-related or security cumulative update is installed corresponding to the fixed build numbers above

A system is affected if it runs any Windows version listed in the affected ranges (including any Windows Server 2012/R2 version) AND lacks the corresponding security update that patches the NTFS driver vulnerability.

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 10.0.14393.9339 / 10.0.17763.9020 / 10.0.19044.7548 or later
Fixed in 10.0.14393.933910.0.17763.902010.0.19044.7548
Interim mitigation

Apply the relevant Microsoft Windows security update for NTFS once released. Prior to patching, restrict local administrative privileges and monitor for indicators of compromise involving unusual NTFS driver behavior.

Recommended fix High confidence

Install the appropriate Windows cumulative update containing the CVE-2026-50309 fix from Microsoft Update (KB article referenced in msrc.microsoft.com)

  1. Identify the current Windows version by running 'winver' or 'systeminfo' to confirm which version and build number is installed
  2. Open Windows Settings > Update & Security > Windows Update
  3. Click 'Check for updates' to download and install all available cumulative updates
  4. After updates install, restart the system when prompted
  5. Verify the installed build number matches or exceeds the fixed version for your Windows release: 10.0.14393.9339 (1607), 10.0.17763.9020 (1809), 10.0.19044.7548 (21h2), 10.0.19045.7548 (22h2), 10.0.26100.8875 (24h2), 10.0.26200.8875 (25h2), or 10.0.28000.2525 (26h1)
  6. For Windows Server 2012/2012 R2, apply the relevant cumulative update from Microsoft Update Catalog that addresses this vulnerability
Caveat Standard Windows update risks apply - ensure backups and system restore points exist before applying updates; some updates may require restart

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
Get the upgrade done

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-2026-50309 — 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-2026-50309 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