CVE-2026-45603: Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Published Jun 9, 2026
·
Updated

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Other sources

Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

— Microsoft

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

— Microsoft

Affected Software

62 affected componentsFixes available
Microsoft Windows Ancillary Function Driver for WinSock
Microsoft Windows 11=24H2
Patch available
Microsoft Windows 11=24H2
Patch available
Microsoft Windows Server 2025
Patch available
Microsoft Windows 11=23H2
Patch available
Microsoft Windows 11=25H2
Patch available
Microsoft Windows 11=23H2
Patch available
Microsoft Windows 11=25H2
Patch available
Microsoft Windows 10 1607<10.0.14393.9234
Microsoft Windows 10 1607<10.0.14393.9234
Microsoft Windows 10 1809<10.0.17763.8880
Microsoft Windows 10 1809<10.0.17763.8880
Microsoft Windows 10 21h2<10.0.19044.7417
Microsoft Windows 10 21h2<10.0.19044.7417
Microsoft Windows 10 21h2<10.0.19044.7417
Microsoft Windows 10 22h2<10.0.19045.7417
Microsoft Windows 10 22h2<10.0.19045.7417
Microsoft Windows 10 22h2<10.0.19045.7417
Microsoft Windows 11 23h2<10.0.22631.7219
Microsoft Windows 11 23h2<10.0.22631.7219
Microsoft Windows 11 24h2<10.0.26100.8655
Microsoft Windows 11 24h2<10.0.26100.8655
Microsoft Windows 11 25h2<10.0.26200.8655
Microsoft Windows 11 25h2<10.0.26200.8655
Microsoft Windows 11 26h1<10.0.28000.2269
Microsoft Windows 11 26h1<10.0.28000.2269
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
Microsoft Windows Server 2016<10.0.14393.9234
Microsoft Windows Server 2019<10.0.17763.8880
Microsoft Windows Server 2022<10.0.20348.5256
Microsoft Windows Server 2025<10.0.26100.32995
Microsoft Windows 10=22H2
10.0.19045.7417
Microsoft Windows 10=22H2
10.0.19045.7417
Microsoft Windows 11=26H1
10.0.28000.2269
Microsoft Windows Server 2025<10.0.26100.32995
10.0.26100.32995
Microsoft Windows 11=26H1
10.0.28000.2269
Microsoft Windows 10=22H2
10.0.19045.7417
Microsoft Windows Server 2025<10.0.26100.32995
10.0.26100.32995
Microsoft Windows 11=24H2
10.0.26100.8655
Microsoft Windows 11=23H2
10.0.22631.7219
Microsoft Windows 11=23H2
10.0.22631.7219
Microsoft Windows 11=24H2
10.0.26100.8655
Microsoft Windows 10=21H2
10.0.19044.7417
Microsoft Windows 10=21H2
10.0.19044.7417
Microsoft Windows 10=21H2
10.0.19044.7417
Microsoft Windows Server 2022<10.0.20348.5256
10.0.20348.5256
Microsoft Windows Server 2019<10.0.17763.8880
10.0.17763.8880
Microsoft Windows 11=25H2
10.0.26200.8655
Microsoft Windows Server 2022<10.0.20348.5256
10.0.20348.5256
Microsoft Windows 11=25H2
10.0.26200.8655
Microsoft Windows Server 2012 R2<6.3.9600.23228
6.3.9600.23228
Microsoft Windows 10=1809
10.0.17763.8880
Microsoft Windows Server 2012<6.2.9200.26132
6.2.9200.26132
Microsoft Windows 10=1809
10.0.17763.8880
Microsoft Windows Server 2012 R2<6.3.9600.23228
6.3.9600.23228
Microsoft Windows Server 2012<6.2.9200.26132
6.2.9200.26132
Microsoft Windows 10=1607
10.0.14393.9234
Microsoft Windows Server 2019<10.0.17763.8880
10.0.17763.8880
Microsoft Windows 10=1607
10.0.14393.9234
Microsoft Windows Server 2016<10.0.14393.9234
10.0.14393.9234
Microsoft Windows Server 2016<10.0.14393.9234
10.0.14393.9234

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19045.7417Patch KB5094127
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.28000.2269Patch KB5095051
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.32995Patch KB5094125
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.8655Patch KB5094126
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.22631.7219Patch KB5093998
  6. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19044.7417Patch KB5094127
  7. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.20348.5256Patch KB5094128
  8. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.17763.8880Patch KB5094123
  9. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26200.8655Patch KB5094126
  10. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.3.9600.23228Patch KB5094041
  11. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.2.9200.26132Patch KB5094042
  12. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.14393.9234Patch KB5094122

Event History

Jun 9, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
Updated
via Microsoft·02:00 PM
WeaknessAffected Software
CVE Published
via MITRE·05:05 PM
Data Sourced
via MITRE·05:05 PM
DescriptionSeverity
Data Sourced
via NVD·05:17 PM
DescriptionSeverityWeaknessAffected Software
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