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CVE-2025-32709: Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2025-05-13
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-05-13 · updated 2026-06-17
• Weakness: CWE-416

Description

Null pointer dereference in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Affected products

• Microsoft Windows 10 Version 1507: before 10.0.10240.21014 — fixed in 10.0.10240.21014
• Microsoft Windows 10 1607: before 10.0.14393.8066 — fixed in 10.0.14393.8066
• Microsoft Windows 10: before 10.0.17763.7314 — fixed in 10.0.17763.7314
• Microsoft Windows 10: before 10.0.19044.5854 — fixed in 10.0.19044.5854
• Microsoft Windows 10: before 10.0.19045.5854 — fixed in 10.0.19045.5854
• Microsoft Windows 11: before 10.0.22621.5335 — fixed in 10.0.22621.5335
• Microsoft Windows 11: before 10.0.22631.5335 — fixed in 10.0.22631.5335
• Microsoft Windows 11: before 10.0.26100.3981 — fixed in 10.0.26100.3981
• Microsoft Windows Server 2008: r2-sp1
• Microsoft Windows Server 2012: r2
• Microsoft Windows Server 2016: before 10.0.14393.8066 — fixed in 10.0.14393.8066
• Microsoft Windows Server 2019: before 10.0.17763.7314 — fixed in 10.0.17763.7314
• Microsoft Windows Server 2022: before 10.0.20348.3692 — fixed in 10.0.20348.3692
• Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.1611 — fixed in 10.0.25398.1611
• Microsoft Windows Server 2025: before 10.0.26100.3981 — fixed in 10.0.26100.3981

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.21014; Microsoft Windows 10 1607 10.0.14393.8066; Microsoft Windows 10 10.0.17763.7314; Microsoft Windows 10 10.0.19044.5854; Microsoft Windows 10 10.0.19045.5854; Microsoft Windows 11 10.0.22621.5335; Microsoft Windows 11 10.0.22631.5335; Microsoft Windows 11 10.0.26100.3981; Microsoft Windows Server 2016 10.0.14393.8066; Microsoft Windows Server 2019 10.0.17763.7314; Microsoft Windows Server 2022 10.0.20348.3692; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1611. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-32709
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-32709

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