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Windows 10 1809Operating system · Microsoft

CVE-2026-20930

HIGH · 7.8 CVSS v3.1 Published 2026-04-14
Fix available
A fix is available. Upgrade to 10.0.17763.8644 / 10.0.19044.7184 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
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Management Services 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

A race condition (TOCTOU vulnerability) exists in Windows Management Services where improper synchronization of shared resources allows a local authorized attacker to manipulate timing and elevate privileges to higher permission levels.

MitigationApply the Microsoft security update for CVE-2026-20930 via Windows Update or WSUS once released, as this vulnerability is patched by Microsoft.

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:< 10.0.17763.8644
Windows 10 21h2Operating system
Affected:< 10.0.19044.7184
Windows 10 22h2Operating system
Affected:< 10.0.19045.7184
Windows 11 23h2Operating system
Affected:< 10.0.22631.6936
Windows 11 24h2Operating system
Affected:< 10.0.26100.8246
Windows 11 25h2Operating system
Affected:< 10.0.26200.8246
Windows Server 2019Operating system
Affected:< 10.0.17763.8644
Windows Server 2022Operating system
Affected:< 10.0.20348.5020

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
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/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 build version
    Open Command Prompt or PowerShell and run 'winver' to see the OS build, or run 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' for detailed version info
    Affected if The displayed build version is lower than the fixed version for your Windows release (17763.8644 for Windows 10 1809/Server 2019, 19044.7184 for Windows 10 21h2, 19045.7184 for Windows 10 22h2, 22631.6936 for Windows 11 23h2, 26100.8246 for Windows 11 24h2, 26200.8246 for Windows 11 25h2, or 20348.5
  2. Verify Windows Management Services status
    Check if the Windows Management Service (WinMgmt) is running by opening Services (services.msc) or running 'Get-Service WinMgmt' in PowerShell
    Affected if The service is running (this is the vulnerable component where the race condition exists)
  3. Confirm local authenticated access exists
    Review local user accounts and group memberships on the system using 'net user' or 'lusrmgr.msc' to determine if any standard users exist
    Affected if Standard (non-admin) local or domain users have access to log onto the system, as the attacker needs local authenticated access to exploit the TOCTOU race condition

You are affected if your Windows build version is lower than the fixed version for your specific Windows release AND standard users have local access to the 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 10.0.17763.8644 / 10.0.19044.7184 / 10.0.19045.7184 or later
Fixed in 10.0.17763.864410.0.19044.718410.0.19045.7184
Interim mitigation

Apply the Microsoft security update for CVE-2026-20930 via Windows Update or WSUS once released, as this vulnerability is patched by Microsoft.

Recommended fix High confidence

Install the appropriate cumulative security update for your Windows version reaching the fixed build number (17763.8644, 19044.7184, 19045.7184, 22631.6936, 26100.8246, 26200.8246, or 20348.5020)

  1. Open Windows Update on the affected Windows system
  2. Check for and install the latest security updates for Windows Management Services
  3. Alternatively, manually download and install the specific security update for your Windows version from the Microsoft Update Catalog
  4. For Windows 10 1809/Windows Server 2019: Install update with build 10.0.17763.8644 or later
  5. For Windows 10 21h2: Install update with build 10.0.19044.7184 or later
  6. For Windows 10 22h2: Install update with build 10.0.19045.7184 or later
  7. For Windows 11 23h2: Install update with build 10.0.22631.6936 or later
  8. For Windows 11 24h2: Install update with build 10.0.26100.8246 or later
Caveat Standard Windows update - no expected breaking changes for this security patch

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

Fix this in Windows 10 1809 Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

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-2026-20930 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