7.8

CVE-2021-33771: Microsoft Windows Kernel Privilege Escalation Vulnerability

CVSS: 7.8v3.1HighKEVAnalyzed
Published 14-07-2021Last modified 10-08-2026
Open JSON

Vulnerability summary

CVE-2021-33771 is a high (CVSS 7.8) vulnerability in Microsoft Windows. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 10.17% chance of exploitation in the next 30 days, higher than 95.6% of scored vulnerabilities.

Overall risk
85/100
0100
Critical · default modelHow is this calculated?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
10.17%
0%100%
Medium · 0.00 pp in 30 days
KEVListedCISA
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 14-07-2021
    PublishedVulnerability first disclosed.
  2. 03-11-2021
    Added to CISA KEVMicrosoft Windows Kernel Privilege Escalation Vulnerability
  3. 17-11-2021
    CISA remediation dueApply updates per vendor instructions.
  4. 10-08-2026
    Last modifiedVulnerability information updated.

Description

Windows Kernel Elevation of Privilege Vulnerability

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

10.17%

Chance of exploitation in the next 30 days

Percentile

96%

Versus all other CVEs

30-day change

0.00 pp

From 10.17% on 19-09-2026

19-09-202619-10-2026
EPSS score
10.17%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
03-11-2021
Federal due date
17-11-2021

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-33771

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Microsoft27 products

1 vendor · 27 products

References

3 links