CVE-2021-33771VulnerabilityPublished 11/03/2021Updated 10/24/2026
CVE-2021-33771: Microsoft Windows Kernel Privilege Escalation Vulnerability
Affects Microsoft WindowsSource CISA KEV
Severity
HighNo CVSS score published yet
- Exploitation
Actively exploited – in CISA KEV since 11/03/2021
- KEV deadline
- 11/17/2021
- EPSS
- 10.2% chance of exploitation in 30 days – higher than 95% of CVEs
What to do
CISA required action
Apply updates per vendor instructions.
Description
CVE-2021-33771 is a high-severity vulnerability in the Microsoft Windows kernel that allows for privilege escalation. The vulnerability is unspecified in detail but has been exploited in the wild. No specific affected versions or patch information is provided in the available data.