dbcve.org
Windows 10 1607Operating system · Microsoft

CVE-2026-33838

HIGH · 7.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 10.0.14393.9140 / 10.0.17763.8755 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
Double free in Windows Message Queuing allows an authorized attacker to elevate privileges 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

A double-free memory corruption vulnerability in Windows Message Queuing (MSMQ) can be exploited by an authorized local attacker to escalate privileges to higher integrity levels. The vulnerability stems from improper memory management when handling MSMQ message objects.

MitigationApply Microsoft security patches for this vulnerability when released. If MSMQ is not required, consider disabling the service. Prioritize patching endpoint systems that handle sensitive data or have high exposure.

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 10 1607Operating system
Affected:< 10.0.14393.9140
Windows 10 1809Operating system
Affected:< 10.0.17763.8755
Windows 10 21h2Operating system
Affected:< 10.0.19044.7291
Windows 10 22h2Operating system
Affected:< 10.0.19045.7291
Windows 11 23h2Operating system
Affected:< 10.0.22631.7079
Windows 11 24h2Operating system
Affected:< 10.0.26100.8390
Windows 11 25h2Operating system
Affected:< 10.0.26200.8390
Windows 11 26h1Operating system
Affected:< 10.0.28000.2113

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. Verify if MSMQ service is installed
    Open Services console (services.msc) and look for 'Message Queuing' service, or run: Get-Service -Name MSMQ in PowerShell
    Affected if The Message Queuing service is listed or returns a valid service object
  2. Confirm MSMQ service is running
    Run: Get-Service -Name MSMQ | Select-Object Status, StartType, or check via services.msc
    Affected if The service status shows as Running (this is required for exploitation)
  3. Check Windows version number
    Run: winver.exe or in PowerShell: [System.Environment]::OSVersion.Version.ToString() or Get-ComputerInfo | Select-Object WindowsVersion
    Affected if The installed version falls below the patched thresholds for your Windows release (1607<14393.9140, 1809<17763.8755, 21h2<19044.7291, 22h2<19045.7291, 23h2<22631.7079, 24h2<26100.8390, 25h2<26200.8390, 26h1<28000.2113)
  4. Check MSMQ components present
    Run: Get-WindowsOptionalFeature -Online | Where-Object {$_.FeatureName -like '*MSMQ*'} or check registry: HKLM\SOFTWARE\Microsoft\MSMQ
    Affected if MSMQ features are enabled (particularly MSMQ Server)

If MSMQ service is installed and running on a Windows version below the patched build number for your release, the environment is likely affected by this privilege escalation 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 10.0.14393.9140 / 10.0.17763.8755 / 10.0.19044.7291 or later
Fixed in 10.0.14393.914010.0.17763.875510.0.19044.7291
Interim mitigation

Apply Microsoft security patches for this vulnerability when released. If MSMQ is not required, consider disabling the service. Prioritize patching endpoint systems that handle sensitive data or have high exposure.

Recommended fix High confidence

Windows 10 1607: 10.0.14393.9140 | Windows 10 1809: 10.0.17763.8755 | Windows 10 21h2: 10.0.19044.7291 | Windows 10 22h2: 10.0.19045.7291 | Windows 11 23h2: 10.0.22631.7079 | Windows 11 24h2: 10.0.26100.8390 | Windows 11 25h2: 10.0.26200.8390 | Windows 11 26h1: 10.0.28000.2113

  1. Check the current Windows version by running 'winver' or 'systeminfo' in command prompt
  2. Identify which Windows 10 or 11 version and build is currently installed
  3. Apply Windows Updates by opening Settings > Update & Security > Windows Update and clicking 'Check for updates'
  4. Alternatively, manually install the appropriate cumulative update for your Windows version from Microsoft Update Catalog
  5. After installation, restart the computer to complete the patch process
  6. Verify the installed version matches or exceeds the fixed build number for your Windows version
Caveat Standard Windows update - minimal risk; ensure backups and compatibility testing for business-critical applications before deploying

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

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.

Scan for this in your stack

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dbcve dependency scanner

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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-2026-33838 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