dbcve.org
Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 3 Mar 2026.
Windows 10 1607Operating system · Microsoft

CVE-2026-21533

HIGH · 7.8 CVSS v3.1 Published 2026-02-10
Fix available
A fix is available. Upgrade to 10.0.14393.8868 / 10.0.17763.8389 or later.
See remediation →
96/100
Remediation priority · Urgent
In the wild 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
Improper privilege management in Windows Remote Desktop 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

Improper privilege management in Windows Remote Desktop allows an authorized attacker to escalate privileges locally by exploiting how the service handles user session context and permission validation.

MitigationApply Microsoft security updates addressing this vulnerability when released, and limit Remote Desktop access to only essential authorized users following least-privilege principles.

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:< 10.0.14393.8868
Windows 10 1809Operating system
Affected:< 10.0.17763.8389
Windows 10 21h2Operating system
Affected:< 10.0.19044.6937
Windows 10 22h2Operating system
Affected:< 10.0.19045.6937
Windows 11 23h2Operating system
Affected:< 10.0.22631.6649
Windows 11 24h2Operating system
Affected:< 10.0.26100.7781
Windows 11 25h2Operating system
Affected:< 10.0.26200.7781
Windows Server 2012Operating system
Affected:all versions= r2

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
    Open Command Prompt and run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the exact Windows version and build number
    Affected if The system runs any of these: Windows 10 1607 (build < 14393.8868), Windows 10 1809 (build < 17763.8389), Windows 10 21h2 (build < 19044.6937), Windows 10 22h2 (build < 19045.6937), Windows 11 23h2 (build < 22631.6649), Windows 11 24h2 (build < 26100.7781), Windows 11 25h2 (build < 26200.7781), Wind
  2. Verify Remote Desktop is enabled
    Open System Properties (right-click This PC > Properties > Remote settings) or run 'reg query "HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server" /v fDenyTSConnections' - a value of 0 means RDP is enabled
    Affected if Remote Desktop is enabled (fDenyTSConnections = 0) on an affected Windows version
  3. Check for pending or installed security updates
    Open Settings > Windows Update > Update history, or run 'wmic qfe list' to list installed hotfixes. Look for post-September 2025 security updates related to Remote Desktop or privilege management
    Affected if No relevant security update for this CVE is installed on an affected Windows version with RDP enabled

You are affected if your system runs any of the listed Windows versions with a build number below the fixed threshold AND has Remote Desktop enabled, and lacks the corresponding security patch.

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 10.0.14393.8868 / 10.0.17763.8389 / 10.0.19044.6937 or later
Fixed in 10.0.14393.886810.0.17763.838910.0.19044.6937
Interim mitigation

Apply Microsoft security updates addressing this vulnerability when released, and limit Remote Desktop access to only essential authorized users following least-privilege principles.

Recommended fix High confidence

Windows 10 1607: 10.0.14393.8868 | Windows 10 1809: 10.0.17763.8389 | Windows 10 21h2: 10.0.19044.6937 | Windows 10 22h2: 10.0.19045.6937 | Windows 11 23h2: 10.0.22631.6649 | Windows 11 24h2: 10.0.26100.7781 | Windows 11 25h2: 10.0.26200.7781 | Windows Server 2012/R2: migrate to supported version as

  1. Identify the current Windows version by running 'winver' or 'systeminfo' in Command Prompt
  2. Note the build number (e.g., 10.0.19045.xxxx) to determine which update is needed
  3. Open Settings > Windows Update and check for available security updates
  4. Install the latest cumulative security update for your Windows version, which should include the fix for this vulnerability
  5. Alternatively, manually download the specific security update from the Microsoft Update Catalog matching your OS version and build
  6. After installation, restart the system to complete the patching process
  7. Verify the installed security update is applied by checking Windows Update history
Caveat Windows Server 2012 and 2012 R2 are end-of-life with no security updates available; migration to a supported Windows Server version is required

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

Fix this in Windows 10 1607 Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-21533 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-21533 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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