CVE-2026-20836
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 Graphics Kernel allows an authorized attacker to elevate privileges locally.
In the news
Third-party coverage- Microsoft CVE Summary - Bleeping Computer
- Microsoft January 2026 Patch Tuesday fixes 3 zero-days, 114 flaws
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 confidenceA race condition vulnerability in the Graphics Kernel involves improper synchronization of shared resources, allowing a local authorized attacker to exploit timing windows and elevate privileges to root or administrator levels.
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< 10.0.14393.8783< 10.0.17763.8276< 10.0.19044.6809< 10.0.19045.6809< 10.0.22631.6491< 10.0.26100.7623< 10.0.26200.7623< 10.0.14393.8783CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Windows versionRun 'winver' from the Start menu or execute 'systeminfo' in Command Prompt and note the OS Version and Build numberAffected if The build number is lower than the threshold for your Windows release (1607: <14393.8783, 1809: <17763.8276, 21h2: <19044.6809, 22h2: <19045.6809, 23h2: <22631.6491, 24h2: <26100.7623, 25h2: <26200.7623, Server 2016: <14393.8783)
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Identify Windows release nameRun 'winver' or check Settings > System > About to confirm the specific Windows 10/11 release (such as 1809, 21h2, 22h2, 23h2, 24h2, 25h2) or Windows Server 2016Affected if The system is running any of the affected releases listed in the version thresholds above
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Confirm Graphics Kernel component presenceThe vulnerability resides in the Windows Graphics Kernel (win32k.sys). Check the file version of C:\Windows\System32\win32k.sys by right-clicking the file, selecting Properties, and viewing the Details tabAffected if The win32k.sys version corresponds to an unpatched build that falls below the affected version thresholds for your Windows release
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Verify local authorized access requirementThis is a local privilege escalation vulnerability requiring the attacker to already have authorized local access to the system (such as a standard user account)Affected if The system has any local user accounts and the Windows version/build falls within the affected ranges - the race condition could be exploited by any local authenticated user to escalate to SYSTEM/Administrator
A system is affected if it runs any Windows 10 version 1607/1809/21h2/22h2, Windows 11 23h2/24h2/25h2, or Windows Server 2016 with a build number below the specified threshold, allowing any local authenticated user to potentially exploit the Graphics Kernel race condition for privilege escalation.
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 · scoped10.0.14393.878310.0.17763.827610.0.19044.6809
Apply vendor-released patches for the Graphics Kernel that implement proper synchronization primitives; given the high CVSS and privilege escalation vector, prioritize deployment to affected systems.
Windows 10 1607/Server 2016: build 10.0.14393.8783 | Windows 10 1809: build 10.0.17763.8276 | Windows 10 21h2: build 10.0.19044.6809 | Windows 10 22h2: build 10.0.19045.6809 | Windows 11 23h2: build 10.0.22631.6491 | Windows 11 24h2: build 10.0.26100.7623 | Windows 11 25h2: build 10.0.26200.7623
- 1. Identify the current Windows version and build number by running `winver` or `systeminfo` in Command Prompt
- 2. Determine which affected version range your system falls into from the CVE details
- 3. For Windows 10 1607/Server 2016: Upgrade to Windows build 10.0.14393.8783 or later
- 4. For Windows 10 1809: Upgrade to Windows build 10.0.17763.8276 or later
- 5. For Windows 10 21h2: Upgrade to Windows build 10.0.19044.6809 or later
- 6. For Windows 10 22h2: Upgrade to Windows build 10.0.19045.6809 or later
- 7. For Windows 11 23h2: Upgrade to Windows build 10.0.22631.6491 or later
- 8. For Windows 11 24h2: Upgrade to Windows build 10.0.26100.7623 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20836 — 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-2026-20836 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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- 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
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