Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-41357

Win32k Elevation of Privilege Vulnerability

Microsoft / Windows 10 Version 21H1 · affected before 10.0.19043.1288

Watch CVE-2021-41357 Browse KEV feed
Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
1.6%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-41357 is Win32k Elevation of Privilege Vulnerability affecting Microsoft Windows 10 Version 21H1 and 6 other products.

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV.

Who is affected?

Microsoft / Windows 10 Version 21H1 affected before 10.0.19043.1288.

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

Microsoft Affected
Windows 10 Version 21H1
Before 10.0.19043.1288
Microsoft Affected
Windows Server 2022
Before 10.0.20348.288
Microsoft Affected
Windows 10 Version 2004
Before 10.0.19041.1288
Microsoft Affected
Windows Server version 2004
Before 10.0.19041.1288
Microsoft Affected
Windows 10 Version 20H2
Before 10.0.19042.1288
Microsoft Affected
Windows Server version 20H2
Before 10.0.19042.1288
Microsoft Affected
Windows 11 version 21H2
Before 10.0.22000.258
Published
13 Oct 2021
Exploitation Reported
25 Apr 2022
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

windows microsoft cisa

CVE References

Exploitation evidence

Why Previdian 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 25 Apr 2022

A trusted third party reported exploitation.

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 2022-04-25 00:00 UTC

Detection

Operational artifacts and observed signals

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

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

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

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

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

EPSS

1.6%

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

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

CVSS v2.0 4.6 Medium

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

Timeline

From disclosure to observed exploitation

  1. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  2. 00:28 UTC

    CVE published

    Vulnerability disclosed publicly

  3. 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.

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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-2021-41357

Sample API response 
{
  "cve_id": "CVE-2021-41357",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.01582,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}