CVE-2026-26177: Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Published Apr 14, 2026
·Updated
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Other sources
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
— Microsoft
Affected Software
57 affected componentsFixes available
Microsoft Windows Ancillary Function Driver for WinSock
Microsoft Windows 10=22H2
Microsoft Windows 10=22H2
Microsoft Windows 10=22H2
Microsoft Windows 10=21H2
Microsoft Windows 10=1809
Microsoft Windows 11=26H1
Microsoft Windows 10=1809
Microsoft Windows 10=21H2
Microsoft Windows 11=26H1
Microsoft Windows Server 2022
Microsoft Windows Server 2019
Microsoft Windows Server 2022
Microsoft Windows Server 2012 R2
Microsoft Windows 10=21H2
Microsoft Windows Server 2012
Microsoft Windows Server 2012
Microsoft Windows Server 2016
Microsoft Windows Server 2012 R2
Microsoft Windows 10=1607
Microsoft Windows Server 2025
Microsoft Windows Server 2016
Microsoft Windows 11=23H2
Microsoft Windows 11=23H2
Microsoft Windows Server 2022, 23H2 Edition
Microsoft Windows 11=25H2
Microsoft Windows Server 2025
Microsoft Windows 11=24H2
Microsoft Windows 10=1607
Microsoft Windows 11=24H2
Microsoft Windows Server 2019
Microsoft Windows 11=25H2
Microsoft Windows 10 1607<10.0.14393.9060
Microsoft Windows 10 1607<10.0.14393.9060
Microsoft Windows 10 1809<10.0.17763.8644
Microsoft Windows 10 1809<10.0.17763.8644
Microsoft Windows 10 21h2<10.0.19044.7184
Microsoft Windows 10 21h2<10.0.19044.7184
Microsoft Windows 10 21h2<10.0.19044.7184
Microsoft Windows 10 22h2<10.0.19045.7184
Microsoft Windows 10 22h2<10.0.19045.7184
Microsoft Windows 10 22h2<10.0.19045.7184
Microsoft Windows 11 23h2<10.0.22631.6936
Microsoft Windows 11 23h2<10.0.22631.6936
Microsoft Windows 11 24h2<10.0.26100.8246
Microsoft Windows 11 24h2<10.0.26100.8246
Microsoft Windows 11 25h2<10.0.26200.8246
Microsoft Windows 11 25h2<10.0.26200.8246
Microsoft Windows 11 26h1<10.0.28000.1836
Microsoft Windows 11 26h1<10.0.28000.1836
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
Microsoft Windows Server 2016<10.0.14393.9060
Microsoft Windows Server 2019<10.0.17763.8644
Microsoft Windows Server 2022<10.0.20348.5020
Microsoft Windows Server 2022 23h2<10.0.25398.2274
Microsoft Windows Server 2025<10.0.26100.32690
Event History
Apr 14, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·04:58 PM
Data Sourced
via MITRE·04:58 PM
DescriptionSeverity
Data Sourced
via NVD·06:16 PM
DescriptionSeverityWeaknessAffected Software
Frequently Asked Questions
1
What is the severity of CVE-2026-26177?
CVE-2026-26177 is rated as a critical vulnerability allowing elevation of privileges.
2
How do I fix CVE-2026-26177?
To fix CVE-2026-26177, apply the latest security update provided by Microsoft.
3
Which systems are affected by CVE-2026-26177?
CVE-2026-26177 affects various versions of Microsoft Windows including Windows 10 and Windows 11.
4
Is CVE-2026-26177 a remote or local vulnerability?
CVE-2026-26177 is a local vulnerability that requires physical access or authenticated user status.
5
What can happen if CVE-2026-26177 is exploited?
If exploited, CVE-2026-26177 can allow an attacker to gain elevated privileges on the affected system.