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7.8 High

CVE-2026-21236 Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate…

Description

Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Affected products and versions

Product Affected versions Fixed in
Windows 11 version 26H1 10.0 10.0.28000.0 → < 10.0.28000.1575 10.0.28000.1575
Windows 10 Version 1809 10.0 10.0.17763.0 → < 10.0.17763.8389 10.0.17763.8389
Windows Server 2019 10.0 10.0.17763.0 → < 10.0.17763.8389 10.0.17763.8389
Windows Server 2019 (Server Core installation) 10.0 10.0.17763.0 → < 10.0.17763.8389 10.0.17763.8389
Windows Server 2022 10.0 10.0.20348.0 → < 10.0.20348.4773 10.0.20348.4773
Windows 10 Version 21H2 10.0 10.0.19044.0 → < 10.0.19044.6937 10.0.19044.6937
Windows 10 Version 22H2 10.0 10.0.19045.0 → < 10.0.19045.6937 10.0.19045.6937
Windows Server 2025 (Server Core installation) 10.0 10.0.26100.0 → < 10.0.26100.32370 10.0.26100.32370
Windows 11 Version 25H2 10.0 10.0.26200.0 → < 10.0.26200.7840 10.0.26200.7840
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Product Affected versions Fixed in
Windows 11 version 22H3 10.0 10.0.22631.0 → < 10.0.22631.6649 10.0.22631.6649
Windows 11 Version 23H2 10.0 10.0.22631.0 → < 10.0.22631.6649 10.0.22631.6649
Windows Server 2022, 23H2 Edition (Server Core installation) 10.0 10.0.25398.0 → < 10.0.25398.2149 10.0.25398.2149
Windows 11 Version 24H2 10.0 10.0.26100.0 → < 10.0.26100.7840 10.0.26100.7840
Windows Server 2025 10.0 10.0.26100.0 → < 10.0.26100.32370 10.0.26100.32370
Windows 10 Version 1607 10.0 10.0.14393.0 → < 10.0.14393.8868 10.0.14393.8868
Windows Server 2016 10.0 10.0.14393.0 → < 10.0.14393.8868 10.0.14393.8868
Windows Server 2016 (Server Core installation) 10.0 10.0.14393.0 → < 10.0.14393.8868 10.0.14393.8868
Windows Server 2012 6.2 6.2.9200.0 → < 6.2.9200.25923 6.2.9200.25923
Windows Server 2012 (Server Core installation) 6.2 6.2.9200.0 → < 6.2.9200.25923 6.2.9200.25923
Windows Server 2012 R2 6.3 6.3.9600.0 → < 6.3.9600.23022 6.3.9600.23022
Windows Server 2012 R2 (Server Core installation) 6.3 6.3.9600.0 → < 6.3.9600.23022 6.3.9600.23022

References

Timeline

  1. Published
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