CVE-2021-28310: Microsoft Win32k Privilege Escalation Vulnerability
CVSS: 7.8v3.1HighKEVAnalyzed
Published 13-04-2021Last modified 21-10-2025
Vulnerability summary
CVE-2021-28310 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in Microsoft Win32k. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 8.40% chance of exploitation in the next 30 days, higher than 94.9% of scored vulnerabilities.
CVSS score
7.8/10
010
High · v3.1 (CVE.org)EPSS score
8.40%
0%100%
Low · +0.07 pp in 30 daysKEVListedCISA
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 13-04-2021PublishedVulnerability first disclosed.
- 03-11-2021Added to CISA KEVMicrosoft Win32k Privilege Escalation Vulnerability
- 17-11-2021CISA remediation dueApply updates per vendor instructions.
- 21-10-2025Last modifiedVulnerability information updated.
Description
Win32k Elevation of Privilege Vulnerability
CVSS metrics
3 scores · 2 sources · 2 versionsHigh 7.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:CSourcesAll 2 agree
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Medium 4.6Preferred score · NVD (NIST)
AV:L/AC:L/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
8.40%
Chance of exploitation in the next 30 days
Percentile
95%
Versus all other CVEs
30-day change
+0.07 pp
From 8.33% on 19-09-2026
19-09-202619-10-2026
EPSS score8.40%
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-2021-28310
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Microsoft18 products
1 vendor · 18 products
References
2 links
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28310X Refsource MISCPatchVendor Advisory- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28310Government ResourceUS Government Resource