known ransomware use

Microsoft Windows Privilege Escalation Vulnerability

Added to KEV
2021-11-03
Federal due date
2022-05-03
Vendor
Microsoft
Product
Windows
EPSS
90.2th percentile (score 0.052, as of 2026-06-08)
NVD CVSS v3.1
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2019-1215

CISA short description

Microsoft Windows contains an unspecified vulnerability due to the way ws2ifsl.sys (Winsock) handles objects in memory, allowing for privilege escalation. Successful exploitation allows an attacker to execute code with elevated privileges.

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.