ExcelApplication · Microsoft

CVE-2026-44803

HIGH · 7.8 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 10.0.14393.9234 / 10.0.17763.8880 or later.
See remediation →
81/100
Remediation priority · High
No privileges

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
Integer overflow or wraparound in Windows Win32K - GRFX allows an unauthorized attacker to execute code locally.

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

Integer overflow or wraparound vulnerability in the Windows Win32K graphics subsystem (GRFX component) allows a local attacker to execute arbitrary code. The flaw exists in kernel-mode graphics handling within win32k.sys, potentially allowing privilege escalation from a low-privileged context.

MitigationApply Microsoft security updates for Windows when released for this vulnerability; maintain current patch levels across all Windows systems to receive kernel subsystem fixes.

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
ExcelApplication
Affected:all versions
PowerpointApplication
Affected:all versions
WordApplication
Affected:all versions
Windows 10 1607Operating system
Affected:< 10.0.14393.9234
Windows 10 1809Operating system
Affected:< 10.0.17763.8880
Windows 10 21h2Operating system
Affected:< 10.0.19044.7417
Windows 10 22h2Operating system
Affected:< 10.0.19045.7417
Windows 11 23h2Operating system
Affected:< 10.0.22631.7219

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 10 version 1607 build number
    Run 'winver' or 'systeminfo | findstr /C:"Build"' and look at the build number (10.0.14393.x)
    Affected if Build is less than 14393.9234
  2. Check Windows 10 version 1809 build number
    Run 'winver' or 'systeminfo | findstr /C:"Build"' and look at the build number (10.0.17763.x)
    Affected if Build is less than 17763.8880
  3. Check Windows 10 version 21h2 build number
    Run 'winver' or 'systeminfo | findstr /C:"Build"' and look at the build number (10.0.19044.x)
    Affected if Build is less than 19044.7417
  4. Check Windows 10 version 22h2 build number
    Run 'winver' or 'systeminfo | findstr /C:"Build"' and look at the build number (10.0.19045.x)
    Affected if Build is less than 19045.7417
  5. Check Windows 11 version 23h2 build number
    Run 'winver' or 'systeminfo | findstr /C:"Build"' and look at the build number (10.0.22631.x)
    Affected if Build is less than 22631.7219

User is affected if running any of the listed Windows 10 or Windows 11 versions with build numbers below the specified thresholds. The Microsoft Office applications listed are not directly vulnerable to this Win32K kernel vulnerability.

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 10.0.14393.9234 / 10.0.17763.8880 / 10.0.19044.7417 or later
Fixed in 10.0.14393.923410.0.17763.888010.0.19044.7417
Interim mitigation

Apply Microsoft security updates for Windows when released for this vulnerability; maintain current patch levels across all Windows systems to receive kernel subsystem fixes.

Recommended fix Moderate confidence

Windows 10 1607 build 10.0.14393.9234+ | Windows 10 1809 build 10.0.17763.8880+ | Windows 10 21h2 build 10.0.19044.7417+ | Windows 10 22h2 build 10.0.19045.7417+ | Windows 11 23h2 build 10.0.22631.7219+

  1. Identify your Windows version by running 'winver' or checking System Information
  2. For Windows 10 1607: Upgrade to build 10.0.14393.9234 or later
  3. For Windows 10 1809: Upgrade to build 10.0.17763.8880 or later
  4. For Windows 10 21h2: Upgrade to build 10.0.19044.7417 or later
  5. For Windows 10 22h2: Upgrade to build 10.0.19045.7417 or later
  6. For Windows 11 23h2: Upgrade to build 10.0.22631.7219 or later
  7. Apply updates via Windows Update or deploy the corresponding Cumulative Update from the Microsoft Update Catalog
  8. Restart the system after applying updates
Caveat Standard Windows update - minimal risk; ensure regular backups and test in staging if possible

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

Fix this in Excel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
Get the upgrade done

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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-44803 — 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-2026-44803 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