dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-56643

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
Use after free in Windows Kernel allows an authorized attacker to elevate privileges 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 use-after-free vulnerability in the Windows Kernel allows a locally authorized attacker to manipulate memory after it has been freed, potentially achieving elevation of privileges from a standard user to SYSTEM or administrative levels.

MitigationApply Microsoft security patches promptly when available; until then, minimize attack surface by restricting local access and monitoring for indicators of compromise.

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:< 10.0.28000.2525
Windows Server 2016Operating system
Affected:< 10.0.14393.9339

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
    Open Command Prompt and run: `systeminfo | findstr /B /C:"OS Name" /C:"OS Version"` or run `winver`
    Affected if The build number displayed is lower than any of the thresholds listed in the affected versions (e.g., < 10.0.14393.9339 for Windows 10 1607/Server 2016, < 10.0.17763.9020 for Windows 10 1809, etc.)
  2. Confirm exact build via registry
    Run: `reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v CurrentBuild`
    Affected if The value of CurrentBuild is less than the fixed build for your Windows release line (e.g., 14393 for 1607, 17763 for 1809, 19044/19045 for 21h2/22h2, 26100 for 11 24h2, 26200 for 11 25h2, 28000 for 11 26h1)
  3. Verify Windows release branch
    Run: `reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v DisplayVersion` to identify if you are on 1607, 1809, 21h2, 22h2, or one of the Windows 11 versions
    Affected if The DisplayVersion corresponds to an affected release (1607, 1809, 21h2, 22h2, 24h2, 25h2, or 26h1) AND the build number is below the fixed threshold for that release

Your system is affected if it runs any of the listed Windows versions with a build number lower than the corresponding fixed threshold, as this is a kernel-level vulnerability present only in unpatched versions.

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 Microsoft security patches promptly when available; until then, minimize attack surface by restricting local access and monitoring for indicators of compromise.

Recommended fix High confidence

Install the appropriate Microsoft Security Update containing the fix for this CVE (consult MSRC for the specific KB article)

  1. 1. Verify current Windows version by running 'winver' or 'systeminfo' in Command Prompt
  2. 2. Open Windows Update by going to Settings > Update & Security > Windows Update
  3. 3. Click 'Check for updates' and install all available updates
  4. 4. For enterprise deployments, verify that the security update matching KB ID for this CVE is installed
  5. 5. After patching, verify the kernel version matches or exceeds the fixed build number for your Windows version
  6. 6. Restart the system if required to complete the installation
Caveat Standard Windows update process - minimal risk; ensure backups of critical systems before applying updates in production environments

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,928.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-56643 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2026-56643 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