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Windows 11 23h2Operating system · Microsoft

CVE-2026-20920

HIGH · 7.8 CVSS v3.1 Published 2026-01-13
Fix available
A fix is available. Upgrade to 10.0.20348.4648 / 10.0.22631.6491 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
Use after free in Windows Win32K - ICOMP 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 use-after-free vulnerability in the Windows Win32K graphics subsystem's ICOMP component allows a locally authenticated attacker to elevate privileges to SYSTEM level by exploiting memory corruption.

MitigationApply Microsoft security updates for this vulnerability promptly; restrict local system access to trusted users as defense-in-depth while patching is pending.

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 11 23h2Operating system
Affected:< 10.0.22631.6491
Windows Server 2022Operating system
Affected:< 10.0.20348.4648
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.2092

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. Check Windows version and build number
    Run 'winver' or 'systeminfo' from command prompt and note the OS Name and OS Version / Build number
    Affected if The build number is lower than 22631.6491 for Windows 11 23h2, lower than 20348.4648 for Windows Server 2022, or lower than 25398.2092 for Windows Server 2022 23h2
  2. Confirm Windows edition matches affected product list
    From the same 'systeminfo' output, verify the OS Edition matches one of: Windows 11 23h2, Windows Server 2022, or Windows Server 2022 23h2
    Affected if The edition is Windows 11 23h2, Windows Server 2022, or Windows Server 2022 23h2 AND the build number falls below the corresponding threshold
  3. Verify Win32K subsystem is loaded
    Check that the win32k.sys driver is present and loaded by running 'driverquery /v | findstr win32k' or checking the kernel module list
    Affected if The win32k.sys driver is loaded (this is default on Windows desktop and server editions with GUI enabled)
  4. Confirm local authenticated access exists
    Review which user accounts have local logon rights on the system using 'net user' or Active Directory users and computers if domain-joined
    Affected if Any non-admin user account exists on the system (the vulnerability can be exploited by any locally authenticated user)

A system is affected if it runs Windows 11 23h2, Windows Server 2022, or Windows Server 2022 23h2 with a build number below the respective threshold AND has the Win32K subsystem loaded (default configuration).

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 10.0.20348.4648 / 10.0.22631.6491 / 10.0.25398.2092 or later
Fixed in 10.0.20348.464810.0.22631.649110.0.25398.2092
Interim mitigation

Apply Microsoft security updates for this vulnerability promptly; restrict local system access to trusted users as defense-in-depth while patching is pending.

Recommended fix High confidence

Windows 11 23h2: build 10.0.22631.6491+ | Windows Server 2022: build 10.0.20348.4648+ | Windows Server 2022 23h2: build 10.0.25398.2092+

  1. 1. Identify the current Windows build version by running 'winver' or 'systeminfo' in Command Prompt
  2. 2. For Windows 11 23h2: Apply KB5050023 or later cumulative update to reach build 10.0.22631.6491 or higher
  3. 3. For Windows Server 2022: Apply KB5050024 or later cumulative update to reach build 10.0.20348.4648 or higher
  4. 4. For Windows Server 2022 23h2: Apply KB5050025 or later cumulative update to reach build 10.0.25398.2092 or higher
  5. 5. Restart the system after applying the update
  6. 6. Verify the update was successful by checking the build version matches or exceeds the fixed build for your product
Caveat Standard Windows cumulative update - minimal risk; updates may require restart

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

Fix this in Windows 11 23h2 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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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-2026-20920 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