dbcve.org
Windows 11 23h2Operating system · Microsoft

CVE-2026-20863

HIGH · 7.0 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 →
72/100
Remediation priority · Elevated
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
Double 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 double-free vulnerability in the Windows Win32K kernel graphics subsystem (ICOMP component) allows a locally authenticated attacker to corrupt heap memory by freeing the same pointer twice, potentially achieving elevated (SYSTEM) privileges.

MitigationApply the Microsoft security update for this vulnerability immediately and enforce the principle of least privilege to limit local user access to trusted personnel only.

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 11 24h2Operating system
Affected:< 10.0.26100.7623
Windows 11 25h2Operating system
Affected:< 10.0.26200.7623
Windows Server 2022Operating system
Affected:< 10.0.20348.4648
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.2092
Windows Server 2025Operating system
Affected:< 10.0.26100.32230

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Windows version and build number
    Run 'winver' from the Run dialog or execute 'systeminfo' in Command Prompt and note the OS Version and Build Number
    Affected if The displayed build number is lower than any of these: 22631.6491 (Win11 23h2), 26100.7623 (Win11 24h2), 26200.7623 (Win11 25h2), 20348.4648 (Server 2022), 25398.2092 (Server 2022 23h2), or 26100.32230 (Server 2025)
  2. Verify Windows edition matches affected product line
    Run 'winver' or check System Properties to confirm whether the system is Windows 11, Windows Server 2022, or Windows Server 2025
    Affected if The system is Windows 11 (any version) or Windows Server 2022/2025 and the build number from step 1 falls below the corresponding threshold
  3. Confirm Win32K kernel graphics subsystem is present
    Check that the system uses the Win32K graphics driver - this is default for all Windows desktop and server installations with GUI; verify by checking for %SystemRoot%\System32\win32k.sys existence
    Affected if The win32k.sys driver exists on the system (standard on all affected Windows installations)
  4. Validate ICOMP component is in use
    The ICOMP component is part of the Windows graphics subsystem and is loaded by win32k.sys during normal graphical operations; no explicit user action required - it is active whenever the desktop is rendered
    Affected if The system has an active graphical desktop session (standard for affected configurations)

The system is affected if it runs any of the listed Windows 11 or Windows Server versions with a build number below the fixed thresholds and uses the Win32K graphics subsystem, which is the 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 the Microsoft security update for this vulnerability immediately and enforce the principle of least privilege to limit local user access to trusted personnel only.

Recommended fix High confidence

Apply Microsoft security patch for CVE-2026-20863 to reach the specified build numbers

  1. Check current Windows build version by running `winver` or `systeminfo | findstr /B /C:"OS Version"`
  2. Open Settings > Windows Update > Check for updates
  3. Install any available security updates for this vulnerability
  4. Restart the system when prompted
  5. Verify the patch was applied by checking the build number matches or exceeds: Windows 11 23h2: 10.0.22631.6491, Windows 11 24h2: 10.0.26100.7623, Windows 11 25h2: 10.0.26200.7623, Windows Server 2022: 10.0.20348.4648, Windows Server 2022 23h2: 10.0.25398.2092, Windows Server 2025: 10.0.26100.32230
Caveat Standard Windows security update; 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
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
Get the upgrade done

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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-2026-20863 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