CVE-2019-0859
Microsoft Win32k Privilege Escalation Vulnerability
What is affected
| Vendor | Microsoft |
|---|---|
| Product | Win32k |
The vulnerability
Microsoft Win32k fails to properly handle objects in memory causing privilege escalation. Successful exploitation allows an attacker to run code in kernel mode.
Required action
Apply updates per vendor instructions.
US federal civilian agencies were required to act by 3 May 2022 under BOD 22-01. The deadline is a compliance date, not a measure of severity — it says nothing about how dangerous the flaw is to anyone else.
Ransomware
CISA records this vulnerability as having been used in ransomware campaigns. That is a confirmed observation, not an assessment of likelihood.
Where this comes from
Every field on this page is taken from the CISA Known Exploited Vulnerabilities catalog, last synced 11 Nov 2026, 21:30. Nothing here is our own assessment. For the technical scoring, see the NVD record below.
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