CVE-2026-20867
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 · uneditedConcurrent 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- Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
- Microsoft CVE Summary - Bleeping Computer
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 confidenceThis is a race condition vulnerability in Windows Management Services where improper synchronization of shared resources allows an authorized local attacker to elevate privileges. The vulnerability stems from concurrent execution issues that can be exploited to gain higher-level access than the attacker initially possesses.
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< 10.0.17763.8276< 10.0.19044.6809< 10.0.19045.6809< 10.0.22631.6491< 10.0.26100.7623< 10.0.26200.7623< 10.0.17763.8276< 10.0.20348.4648CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check Windows build numberRun 'winver' from command prompt or 'systeminfo' and locate the 'OS Build' numberAffected if The build number is lower than the threshold for your specific Windows version (17763.8276 for Windows 10 1809/Server 2019, 19044.6809 for Windows 10 21h2, 19045.6809 for Windows 10 22h2, 22631.6491 for Windows 11 23h2, 26100.7623 for Windows 11 24h2, 26200.7623 for Windows 11 25h2, or 20348.4648 fo
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Identify Windows editionRun 'winver' or check 'systeminfo' 'OS Name' to determine if you are running Windows 10 1809, 21h2, 22h2, Windows 11 23h2/24h2/25h2, Windows Server 2019, or Windows Server 2022Affected if The detected edition matches one listed in the affected products with a build number below its corresponding threshold
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Confirm Windows Management Services presenceOpen Services console (services.msc) and look for 'Windows Management Instrumentation' service or check for 'Windows Management Services' process in Task ManagerAffected if The Windows Management Services or WMI service is present and running on the system
You are affected if your Windows build number is lower than the threshold listed for your specific Windows edition and Windows Management Services is available on your system.
Generated from the published advisory. Verify against your own configuration.
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 · scoped10.0.17763.827610.0.19044.680910.0.19045.6809
Apply Microsoft security patches for Windows Management Services when available. Follow least-privilege principles and limit local administrator access to reduce attack surface.
Install the appropriate Windows Security Update (CVE-2026-20867) via Windows Update, WSUS, or Microsoft Update Catalog to reach the fixed version thresholds (e.g., 10.0.17763.8276, 10.0.19044.6809, 10.0.19045.6809, 10.0.22631.6491, 10.0.26100.7623, 10.0.26200.7623, or 10.0.20348.4648 depending on Wi
- Identify the current Windows version by running 'winver' or 'systeminfo' in Command Prompt
- Determine the applicable security update based on the installed Windows version and build number
- For Windows 10 1809/Server 2019: Apply KB5055529 (or latest cumulative update) to reach version 10.0.17763.8276
- For Windows 10 21h2: Apply KB5055519 (or latest cumulative update) to reach version 10.0.19044.6809
- For Windows 10 22h2: Apply KB5055527 (or latest cumulative update) to reach version 10.0.19045.6809
- For Windows 11 23h2: Apply KB5055523 (or latest cumulative update) to reach version 10.0.22631.6491
- For Windows 11 24h2: Apply KB5055525 (or latest cumulative update) to reach version 10.0.26100.7623
- For Windows 11 25h2: Apply KB5055520 (or latest cumulative update) to reach version 10.0.26200.7623
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20867 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-20867 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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