CVE-2021-33771
HighExploitedPublic exploitWindows Kernel Elevation of Privilege Vulnerability
Published Jul 14, 2021 · Updated Aug 10, 2026
Key Facts
Patch immediately- CVE-2021-33771 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Windows 10 1507 (Microsoft), Windows 10 1607 (Microsoft), Windows 10 1809 (Microsoft) and 13 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 13, 2021. Public exploit code is available.
- EPSS estimates a 10% probability of exploitation in the next 30 days.
- Fixed versions are available, including Windows 10 1507 10.0.10240.19003, Windows 10 1607 10.0.14393.4530, Windows 10 1809 10.0.17763.2061.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
10%
Higher than 95.6% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-33771 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
Windows Kernel Elevation of Privilege Vulnerability
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | Nov 17, 2021 | Not reported |
| Industry KEV feed | Jul 13, 2021 | Nov 17, 2021 | Not reported |
| CIRCL KEV | Nov 3, 2021 | Nov 17, 2021 | Not reported |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
40 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 10 1507Microsoft | 10.0.10240.19003 | 10.0.10240.19003 |
| Windows 10 1607Microsoft | 10.0.14393.4530 | 10.0.14393.4530 |
| Windows 10 1809Microsoft | 10.0.17763.2061, 10.0.18363.1679, 10.0.19041.1110 | 10.0.17763.2061 |
| Windows 10 1909Microsoft | 10.0.18363.1679 | 10.0.18363.1679 |
| Windows 10 2004Microsoft | See advisory | 10.0.19041.1110 |
Patched Releases
Windows 10 1507
10.0.10240.19003
Windows 10 1607
10.0.14393.4530
Windows 10 1809
10.0.17763.2061, 10.0.18363.1679, 10.0.19041.1110
Windows 10 1909
10.0.18363.1679
Windows 10 2004
10.0.19041.1110
windows 10 20H2
10.0.19042.1110
windows 10 21H1
10.0.19043.1110
Windows 8.1
6.3.9600.20069
Windows Rt 8.1
6.3.9600.20069
Windows Server 2004
10.0.19041.1110
windows server 2012 R2
6.3.9600.20069
Windows Server 2016
10.0.14393.4530
Windows Server 2019
10.0.17763.2061
windows server 20H2
10.0.19042.1110
Timeline
Added to Industry KEV feed
Jul 13, 2021
Publicly disclosed
Jul 14, 2021
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Aug 10, 2026
References
- patchhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33771
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
Windows Kernel Elevation of Privilege Vulnerability
Affected: Windows 10 1507 (Microsoft) versions 10.0.10240.19003; Windows 10 1607 (Microsoft) versions 10.0.14393.4530; Windows 10 1809 (Microsoft) versions 10.0.17763.2061, 10.0.18363.1679, 10.0.19041.1110, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jul 13, 2021.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of Nov 17, 2021.
Public exploit code is available.
Fixed versions are available, including Windows 10 1507 10.0.10240.19003, Windows 10 1607 10.0.14393.4530, Windows 10 1809 10.0.17763.2061.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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