Vulnerability report

Trusted Third Party Report Confirmed Confidence In CISA KEV

CVE-2021-1732

Windows Win32k Elevation of Privilege Vulnerability

Microsoft / Windows 10 Version 1803 · affected before publication

Watch CVE-2021-1732 Browse KEV feed
Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Trusted Third Party Report
EPSS
78.4%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-1732 is Windows Win32k Elevation of Privilege Vulnerability affecting Microsoft Windows 10 Version 1803 and 10 other products.

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Also reported by third-party sources. Confidence is confirmed.

Who is affected?

Affected products include Microsoft / Windows 10 Version 1803 and 10 other products, including affected before publication.

What should we do?

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

Overview

Windows Win32k Elevation of Privilege Vulnerability

Windows Win32k Elevation of Privilege Vulnerability

Microsoft Affected
Windows 10 Version 1803
Before publication
Microsoft Affected
Windows 10 Version 1809
Before publication
Microsoft Affected
Windows Server 2019
Before publication
Microsoft Affected
Windows Server 2019 (Server Core installation)
Before publication
Microsoft Affected
Windows 10 Version 1909
Before publication
Microsoft Affected
Windows Server, version 1909 (Server Core installation)
Before publication
Microsoft Affected
Windows 10 Version 2004
Before publication
Microsoft Affected
Windows Server version 2004
Before publication
Microsoft Affected
Windows 10 Version 20H2
Before publication
Microsoft Affected
Windows Server version 20H2
Before publication
Published
25 Feb 2021
Exploitation Attempts Reported
03 Nov 2021
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

microsoft malware windows ransomware metasploit cisa metasploit_scanner

CVE References

Exploitation evidence

Evidence of exploitation attempts

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

Exploitation Attempts Observed in the Wild

CISA

Recorded 03 Nov 2021

A trusted third party reported exploitation attempts.

Targeted by Malware-Related Exploitation Attempts

CISA

Recorded 03 Nov 2021

Exploitation attempts against this vulnerability are associated with malware-related payloads.

Proof of concept available

GitHub

Recorded 05 Mar 2021

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

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

Learn about Pro API access
Source Added
CISA First 2021-11-03 00:00 UTC
Tenable Blog 2026-06-02 14:20 UTC
CVE 2026-08-12 04:21 UTC

Detection

Operational artifacts and observed signals

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

Virtual patch status

No Previdian 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_2022_21882_win32k.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High

Potential damage if exploited. Separate from whether attackers are using it.

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

78.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Out-of-bounds Write CWE-787

Recent mention · Tenable Blog

Inside the customer environment: Where threat actors, vulnerabilities, and exposed assets intersect

Tenable Research has developed a graph-based model linking 600+ threat groups to real-world customer exposures. It reveals which vulnerabilities sit at the intersection of severity, active exploitation, and organizational risk.Key takeawaysThe "patch everything" strategy is...

Read full advisory

All CVSS Scores

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

CVSS v2.0 4.6 Medium

AV:L/AC:L/Au:N/C:P/I:P/A:P

All Mentions

Recent mention · Tenable Blog

Inside the customer environment: Where threat actors, vulnerabilities, and exposed assets intersect

Tenable Blog · 27 May 2026

Tenable Research has developed a graph-based model linking 600+ threat groups to real-world customer exposures. It reveals which vulnerabilities sit at the intersection of severity, active exploitation, and organizational risk.Key takeawaysThe "patch everything" strategy is dead: Vulnerability prioritization based on exploitation risk offers a path forward. A directed graph model linking 600+ threat actors to vulnerabilities in 7,800 customer environments reveals that 68% of organizations carry at least one CVE previously exploited by a named adversary, and 321 tracked threat groups can...

Potential Proof of Concepts

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

exploitblizzard/Windows-Privilege-Escalation-CVE-2021-1732

github · Created 2021-04-25 12:55:15 UTC · 31 stars · AI assessment 90%

Read my blog for more info -

KaLendsi/CVE-2021-1732-Exploit

github · Created 2021-03-05 02:11:10 UTC · 417 stars · AI assessment 90%

CVE-2021-1732 Exploit

Timeline

From disclosure to observed exploitation attempts

  1. 04:21 UTC

    KEV confirmed by CVE

    Exploitation attempts reported by an external source

  2. 14:20 UTC

    KEV confirmed by Tenable Blog

    Exploitation attempts reported by an external source

  3. 15:02 UTC

    Metasploit module available

    Exploit module available

  4. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. 00:00 UTC

    Targeted by malware-related exploitation attempts

    Malware-related exploitation attempts or payloads reported

  6. 02:11 UTC

    Public PoC available

    Public proof-of-concept code published

  7. 23:01 UTC

    CVE published

    Vulnerability disclosed publicly

  8. 00:00 UTC

    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.

Start 14-day Pro trial Read API docs
  • 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-2021-1732

Sample API response 
{
  "cve_id": "CVE-2021-1732",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.78376,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}