Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

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Summary

CVECVE-2026-33100
StatePUBLISHED
Assignermicrosoft
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-14 18:17:32 UTC
Updated2026-04-14 18:17:32 UTC
DescriptionUse after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Risk And Classification

Primary CVSS: v3.1 7 HIGH from [email protected]

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-416 | CWE-416 CWE-416: Use After Free

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNACVSS7HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Microsoft Windows 10 Version 1607 affected 10.0.14393.0 10.0.14393.9060 custom 32-bit Systems, x64-based Systems
CNA Microsoft Windows 10 Version 1809 affected 10.0.17763.0 10.0.17763.8644 custom 32-bit Systems, x64-based Systems
CNA Microsoft Windows 10 Version 21H2 affected 10.0.19044.0 10.0.19044.7184 custom 32-bit Systems, ARM64-based Systems, x64-based Systems
CNA Microsoft Windows 10 Version 22H2 affected 10.0.19045.0 10.0.19045.7184 custom 32-bit Systems, ARM64-based Systems, x64-based Systems
CNA Microsoft Windows 11 Version 22H3 affected 10.0.22631.0 10.0.22631.6936 custom ARM64-based Systems
CNA Microsoft Windows 11 Version 23H2 affected 10.0.22631.0 10.0.22631.6936 custom x64-based Systems
CNA Microsoft Windows 11 Version 24H2 affected 10.0.26100.0 10.0.26100.32690 custom ARM64-based Systems, x64-based Systems
CNA Microsoft Windows 11 Version 25H2 affected 10.0.26200.0 10.0.26200.8246 custom ARM64-based Systems, x64-based Systems
CNA Microsoft Windows 11 Version 26H1 affected 10.0.28000.0 10.0.28000.1836 custom ARM64-based Systems, x64-based Systems
CNA Microsoft Windows Server 2012 affected 6.2.9200.0 6.2.9200.26026 custom x64-based Systems
CNA Microsoft Windows Server 2012 Server Core Installation affected 6.2.9200.0 6.2.9200.26026 custom x64-based Systems
CNA Microsoft Windows Server 2012 R2 affected 6.3.9600.0 6.3.9600.23132 custom x64-based Systems
CNA Microsoft Windows Server 2012 R2 Server Core Installation affected 6.3.9600.0 6.3.9600.23132 custom x64-based Systems
CNA Microsoft Windows Server 2016 affected 10.0.14393.0 10.0.14393.9060 custom x64-based Systems
CNA Microsoft Windows Server 2016 Server Core Installation affected 10.0.14393.0 10.0.14393.9060 custom x64-based Systems
CNA Microsoft Windows Server 2019 affected 10.0.17763.0 10.0.17763.8644 custom x64-based Systems
CNA Microsoft Windows Server 2019 Server Core Installation affected 10.0.17763.0 10.0.17763.8644 custom x64-based Systems
CNA Microsoft Windows Server 2022 affected 10.0.20348.0 10.0.20348.5020 custom x64-based Systems
CNA Microsoft Windows Server 2022 23H2 Edition Server Core Installation affected 10.0.25398.0 10.0.25398.2274 custom x64-based Systems
CNA Microsoft Windows Server 2025 affected 10.0.26100.0 10.0.26100.32690 custom x64-based Systems
CNA Microsoft Windows Server 2025 Server Core Installation affected 10.0.26100.0 10.0.26100.32690 custom x64-based Systems

References

ReferenceSourceLinkTags
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33100 [email protected] msrc.microsoft.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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