Microsoft Win32k Privilege Escalation Vulnerability

Added to KEV
2022-05-23
Federal due date
2022-06-13
Vendor
Microsoft
Product
Win32k
EPSS
97.9th percentile (score 0.504, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2018-8589

CISA short description

A privilege escalation vulnerability exists when Windows improperly handles calls to Win32k.sys. An attacker who successfully exploited this vulnerability could run remote code in the security context of the local system.

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.