Microsoft Win32k Privilege Escalation Vulnerability

Added to KEV
2022-04-25
Federal due date
2022-05-16
Vendor
Microsoft
Product
Win32k
EPSS
88.9th percentile (score 0.041, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2021-40450

CISA short description

Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.

Required action

Apply updates per vendor instructions.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.