Windows 10Operating system · Microsoft

CVE-2021-34487

HIGH · 7.0 CVSS v3.1 Published 2021-08-12
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
72/100
Remediation priority · Elevated
Zero-click Patch available

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
Windows Event Tracing Elevation of Privilege Vulnerability

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
How this class of weakness works · CWE-269

Privileges are granted, or fail to be dropped, incorrectly, so an action runs with more power than it should. An attacker who reaches that path inherits the excess privilege. The fix is least-privilege throughout, with explicit, checked transitions whenever privilege changes.

General guidance for the improper privilege management class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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 10Operating system
Affected:= 20h2= 21h1= 1607= 1809= 1909= 2004
Windows Server 2016Operating system
Affected:all versions= 20h2= 2004
Windows Server 2019Operating system
Affected:all versions

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

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
Patch available Apply the vendor patch
Recommended fix High confidence
  1. Identify your Windows version and build number by running 'winver' or 'systeminfo' from command prompt
  2. Navigate to Microsoft Update Catalog at https://www.catalog.update.microsoft.com/ and search for 'CVE-2021-34487' or the corresponding KB number
  3. Download the security update specific to your Windows version and architecture (x64, x86, or ARM64)
  4. Run the downloaded update installer with administrator privileges
  5. Restart the computer when prompted to complete the installation
  6. Verify the update was installed successfully by checking Windows Update history or running 'systeminfo' to confirm the new build number

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

We can apply and verify the patch for your build — typical engagement from $1,950. Get the patch applied

Scan for this in your stack

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dbcve dependency scanner

Check whether your project pulls in CVE-2021-34487 — 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-2021-34487 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