Windows 10 1809Operating system · Microsoft

CVE-2026-20873

HIGH · 7.8 CVSS v3.1 Published 2026-01-13
Fix available
A fix is available. Upgrade to 10.0.17763.8276 / 10.0.19044.6809 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.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 7mo 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 race condition vulnerability exists in Windows Management Services where concurrent execution of certain operations shares resources without proper synchronization. An authorized attacker with local access can exploit this timing vulnerability to elevate privileges from their current authenticated context to higher-level system privileges.

MitigationApply Microsoft security updates for Windows Management Services when released. Prioritize patching domain controllers and systems with privileged access requirements. Limit local administrative privileges and monitor for suspicious process activity.

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:< 10.0.17763.8276
Windows 10 21h2Operating system
Affected:< 10.0.19044.6809
Windows 10 22h2Operating system
Affected:< 10.0.19045.6809
Windows 11 23h2Operating system
Affected:< 10.0.22631.6491
Windows 11 24h2Operating system
Affected:< 10.0.26100.7623
Windows 11 25h2Operating system
Affected:< 10.0.26200.7623
Windows Server 2019Operating system
Affected:< 10.0.17763.8276
Windows Server 2022Operating system
Affected:< 10.0.20348.4648

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 number
    Run 'winver' from command prompt or execute 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to retrieve the full build version including the revision number
    Affected if The build number is lower than the affected version for your Windows release (e.g., Windows 10 22h2 builds below 10.0.19045.6809)
  2. Verify Windows Management Services component
    Check if the Windows Management Instrumentation (WMI) service or Windows Management Services are present by running 'sc query Winmgmt' or reviewing installed Windows features via 'Get-WindowsOptionalFeature -Online' in PowerShell
    Affected if The Windows Management service is installed and running on the system
  3. Confirm local authentication context
    Determine if the user checking this system has any elevated or administrative privileges by running 'whoami /groups' and checking for membership in Administrators, Backup Operators, or similar privileged groups
    Affected if The current user has local administrative rights or lower-privileged access that could be exploited for privilege escalation
  4. Cross-reference build with CVE version matrix
    Compare the detected build number against the affected version ranges: 17763.8276 (1809/Server 2019), 19044.6809 (21h2), 19045.6809 (22h2), 22631.6491 (23h2), 26100.7623 (24h2), 26200.7623 (25h2), or 20348.4648 (Server 2022)
    Affected if The installed build falls below any of these threshold versions for the corresponding Windows release

A system is affected if it runs an unpatched Windows version with a build number below the CVE threshold AND has Windows Management Services enabled, allowing a local authenticated user to potentially exploit the race condition for privilege escalation.

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 10.0.17763.8276 / 10.0.19044.6809 / 10.0.19045.6809 or later
Fixed in 10.0.17763.827610.0.19044.680910.0.19045.6809
Interim mitigation

Apply Microsoft security updates for Windows Management Services when released. Prioritize patching domain controllers and systems with privileged access requirements. Limit local administrative privileges and monitor for suspicious process activity.

Recommended fix High confidence

Windows 10 1809 to build 10.0.17763.8276 or later | Windows 10 21h2 to build 10.0.19044.6809 or later | Windows 10 22h2 to build 10.0.19045.6809 or later | Windows 11 23h2 to build 10.0.22631.6491 or later | Windows 11 24h2 to build 10.0.26100.7623 or later | Windows 11 25h2 to build 10.0.26200.7623

  1. Identify the current Windows build version by running 'winver' or 'systeminfo' in Command Prompt
  2. Determine which Windows version and build you are running from the affected list
  3. Apply the appropriate Windows security update for your version - check Windows Update or Microsoft Update Catalog for the latest cumulative update containing the fix for CVE-2026-20873
  4. Verify the update was installed successfully by checking Windows Update history
  5. Confirm the build number has been updated to or beyond the fixed version: 10.0.17763.8276 (Windows 10 1809/Server 2019), 10.0.19044.6809 (Windows 10 21h2), 10.0.19045.6809 (Windows 10 22h2), 10.0.22631.6491 (Windows 11 23h2), 10.0.26100.7623 (Windows 11 24h2), 10.0.26200.7623 (Windows 11 25h2), or 10.0.20348.4648 (Windows Server 2022)
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
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,872.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-20873 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2026-20873 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