CVE-2021-1732
HighExploitedPublic exploitWindows Win32k Elevation of Privilege Vulnerability
Published Feb 10, 2021 · Updated Aug 12, 2026 · Also known as TR-21-0124
Key Facts
Patch immediately- CVE-2021-1732 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Windows 10 1803 (Microsoft), Windows 10 1809 (Microsoft), Windows 10 1909 (Microsoft) and 6 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Dec 10, 2020 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 78% probability of exploitation in the next 30 days.
- Fixed versions are available, including Windows 10 1803 publication, Windows 10 1809 publication, Windows 10 1909 publication.
- 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)
78%
Higher than 99.5% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-1732 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
Windows Win32k Elevation of Privilege Vulnerability
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | Nov 17, 2021 | Known |
| Industry KEV feed | Dec 10, 2020 | Nov 17, 2021 | Known |
| CIRCL KEV | Nov 3, 2021 | Nov 17, 2021 | Known |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
22 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 10 1803Microsoft | See advisory | publication |
| Windows 10 1809Microsoft | See advisory | publication |
| Windows 10 1909Microsoft | See advisory | publication |
| Windows 10 2004Microsoft | See advisory | n/a |
| windows 10 20H2Microsoft | See advisory | publication |
Patched Releases
Windows 10 1803
publication
Windows 10 1809
publication
Windows 10 1909
publication
windows 10 20H2
publication
Windows Server 1909
publication
Windows Server 2004
publication
Windows Server 2019
publication
windows server 20H2
publication
Timeline
Added to Industry KEV feed
Dec 10, 2020
Publicly disclosed
Feb 10, 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 12, 2026
Weakness Type
- CWE-787 Out-of-bounds Write
References
- advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1732
- advisoryhttps://us-cert.cisa.gov/
- advisoryhttps://us-cert.cisa.gov/ncas/current-activity/2021/02/09/microsoft-warns-windows-win32k-privilege-escalation
- advisoryUSOM advisory
- patchhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1732
FAQ
Common Questions.
Windows Win32k Elevation of Privilege Vulnerability
Affected: Windows 10 1803 (Microsoft); Windows 10 1809 (Microsoft); Windows 10 1909 (Microsoft), 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 Dec 10, 2020 and is known to be used in ransomware campaigns.
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 1803 publication, Windows 10 1809 publication, Windows 10 1909 publication.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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