CVE-2021-28310
HighExploitedPublic exploitWin32k Elevation of Privilege Vulnerability
Published Apr 13, 2021 · Updated Oct 30, 2025
Key Facts
Patch immediately- CVE-2021-28310 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 Apr 13, 2021. Public exploit code is available.
- EPSS estimates a 8.4% 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)
8.4%
Higher than 94.9% 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-2021-28310 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
Win32k 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 | Apr 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
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
Publicly disclosed
Apr 13, 2021
Added to Industry KEV feed
Apr 13, 2021
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Oct 30, 2025
Weakness Type
- CWE-787 Out-of-bounds Write
References
- patchhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28310
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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 Apr 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 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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