CISA KEV · Known exploitedHigh

CVE-2021-40450

Microsoft Win32k

CVE-2021-40450 affects Microsoft Win32k. Review the CVSS score, exploitation signals, affected versions, remediation status, and linked source material before making a change.

CVSS: 7.8
EPSS: 1.97%
CISA KEV: Listed
Published: 2021.10.13

PRIORITY ASSESSMENT

Immediate review

CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog.

Known exploitationConfirmed by CISA KEV

Exploit probability1.97%

Technical severityCVSS 7.8

Vulnerability overview

CVE-2021-40450 affects Microsoft Win32k. Review the CVSS score, exploitation signals, affected versions, remediation status, and linked source material before making a change.

Affected product and versions

Product: Microsoft Win32k
Affected versions: 10.0.0, < 10.0.17763.2237, < 10.0.18363.1854, < 10.0.19041.1288, < 10.0.19042.1288, < 10.0.19043.1288, < 10.0.22000.258, < 10.0.20348.288
Fixed versions: 10.0.17763.2237, 10.0.18363.1854, 10.0.19041.1288, 10.0.19042.1288, 10.0.19043.1288, 10.0.22000.258, 10.0.20348.288

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

CISA required action

Apply updates per vendor instructions.

Due date: 2022.05.16

1
Identify
Confirm that Microsoft Win32k and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE: Not available
KEV added: 2022.04.25
Ransomware use: 미확인