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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Nov 2021.
Windows 10 1507Operating system · Microsoft

CVE-2021-31979

HIGH · 7.8 CVSS v3.1 Developing Published 2021-07-14
Fix available
A fix is available. Upgrade to 10.0.10240.19003 / 10.0.14393.4530 or later.
See remediation →
96/100
Remediation priority · Urgent
In the wild 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 Kernel 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 · low confidence

Windows Kernel Elevation of Privilege Vulnerability in the Windows kernel that allows a local authenticated attacker to execute arbitrary code in kernel mode, potentially achieving SYSTEM privileges.

MitigationApply the Microsoft security update for CVE-2021-31979, released as part of the June 2021 Patch Tuesday. Prioritize patching given the high CVSS score and EoP classification.

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 1507Operating system
Affected:< 10.0.10240.19003
Windows 10 1607Operating system
Affected:< 10.0.14393.4530
Windows 10 1809Operating system
Affected:< 10.0.17763.2061
Windows 10 1909Operating system
Affected:< 10.0.18363.1679
Windows 10 2004Operating system
Affected:< 10.0.19041.1110
Windows 10 20h2Operating system
Affected:< 10.0.19042.1110
Windows 10 21h1Operating system
Affected:< 10.0.19043.1110
Windows 7Operating 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
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 build number
    Open Command Prompt or PowerShell and run `systeminfo | findstr /B /C:"OS Name" /C:"OS Version" /C:"Build Number"`. Alternatively, run `winver` to see the version and build in the GUI.
    Affected if The build number falls below any of these thresholds: 10240.19003 (1507), 14393.4530 (1607), 17763.2061 (1809), 18363.1679 (1909), 19041.1110 (2004), 19042.1110 (20h2), 19043.1110 (21h1). Windows 7 any version is also affected.
  2. Confirm Windows 10 version release
    If using Windows 10, identify the release (1507, 1607, 1809, 1909, 2004, 20h2, or 21h1) by running `reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v ReleaseId` in Command Prompt or checking the System Properties.
    Affected if The system is running any of the affected Windows 10 releases at a build number lower than the corresponding threshold listed in step 1.
  3. Verify patch installation status
    Run `systeminfo | findstr "Hotfix(s)"` or check Windows Update history for June 2021 security updates. The patch for CVE-2021-31979 is part of the June 2021 cumulative update.
    Affected if The June 2021 security updates are not installed, or no corresponding hotfix for CVE-2021-31979 appears in the installed updates list.

A system is affected if it runs Windows 10 (any release from 1507 through 21h1) below the specified build thresholds, or any version of Windows 7, and the June 2021 security updates have not been applied.

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 10.0.10240.19003 / 10.0.14393.4530 / 10.0.17763.2061 or later
Fixed in 10.0.10240.1900310.0.14393.453010.0.17763.2061
Vendor patch portal.msrc.microsoft.com →
Interim mitigation

Apply the Microsoft security update for CVE-2021-31979, released as part of the June 2021 Patch Tuesday. Prioritize patching given the high CVSS score and EoP classification.

Recommended fix High confidence

Windows 10 1507 to 10.0.10240.19003+ | Windows 10 1607 to 10.0.14393.4530+ | Windows 10 1809 to 10.0.17763.2061+ | Windows 10 1909 to 10.0.18363.1679+ | Windows 10 2004 to 10.0.19041.1110+ | Windows 10 20h2 to 10.0.19042.1110+ | Windows 10 21h1 to 10.0.19043.1110+

  1. 1. Identify the current Windows version and build by running 'winver' or 'systeminfo' in Command Prompt
  2. 2. For Windows 7: Migrate to a supported Windows version (Windows 7 is end-of-life with no security updates)
  3. 3. For Windows 10 1507: Upgrade to build 10.0.10240.19003 or later
  4. 4. For Windows 10 1607: Upgrade to build 10.0.14393.4530 or later
  5. 5. For Windows 10 1809: Upgrade to build 10.0.17763.2061 or later
  6. 6. For Windows 10 1909: Upgrade to build 10.0.18363.1679 or later
  7. 7. For Windows 10 2004: Upgrade to build 10.0.19041.1110 or later
  8. 8. For Windows 10 20h2: Upgrade to build 10.0.19042.1110 or later
Caveat Windows 7 has no security support; migrate to supported Windows OS | Major Windows 10 version upgrades may require reconfiguration of apps and settings

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

Fix this in Windows 10 1507 Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-31979 — 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-2021-31979 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