KEV Intelligence

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-40449

Win32k Elevation of Privilege Vulnerability

Microsoft / Windows 10 Version 1809 · affected before 10.0.17763.2237

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Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
74.1%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-40449 is Win32k Elevation of Privilege Vulnerability affecting Microsoft Windows 10 Version 1809 and 26 other products.

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Microsoft / Windows 10 Version 1809 affected before 10.0.17763.2237.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Win32k Elevation of Privilege Vulnerability

Win32k Elevation of Privilege Vulnerability

Vendor Product Affected Status
Microsoft Windows Server 2012 R2 Before 6.3.9600.20144 Affected
Microsoft Windows Server 2012 R2 (Server Core installation) Before 6.3.9600.20144 Affected
Published
13 Oct 2021
Exploitation Reported
17 Nov 2021
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

ransomware metasploit microsoft cisa malware windows

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 17 Nov 2021

Independent exploitation attestation added to the KEV Intelligence record.

Used in malware

CISA

Recorded 17 Nov 2021

Malware families have been linked to exploitation of this CVE.

Proof of concept available

GitHub

Recorded 20 Oct 2021

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
CISA First 2021-11-17 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/local/cve_2021_40449.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

EPSS

74.1%

Weaknesses

Use After Free CWE-416

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Kristal-g/CVE-2021-40449_poc

github · Created 2021-11-07 16:15:19 UTC · 52 stars · AI assessment 90%

Exploit for CVE-2021-40449

hakivvi/CVE-2021-40449

github · Created 2021-10-25 04:58:49 UTC · 41 stars · AI assessment 90%

LPE exploit for a UAF in Windows (CVE-2021-40449).

KaLendsi/CVE-2021-40449-Exploit

github · Created 2021-10-20 09:24:36 UTC · 96 stars · AI assessment 90%

windows 10 14393 LPE

cve_2021_40449

metasploit · Created Unknown

Metasploit module for CVE-2021-40449

Timeline

From disclosure to observed exploitation

  1. Metasploit module available

    Exploit module available

  2. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. First public exploitation report

    Exploit observed in malware

  4. Public PoC available

    Public proof-of-concept code published

  5. CVE published

    Vulnerability disclosed publicly

  6. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-40449

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-40449",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.74129,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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