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CVE-2026-68820: Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability

• Severity: high (CVSS 7.0 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2026-08-11
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-11 · updated 2026-10-26
• Weakness: CWE-416

Description

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

Affected products

• Microsoft Windows 10 1607: before 10.0.14393.9418 — fixed in 10.0.14393.9418
• Microsoft Windows 10: before 10.0.17763.9115 — fixed in 10.0.17763.9115
• Microsoft Windows 10: before 10.0.19044.7663 — fixed in 10.0.19044.7663
• Microsoft Windows 10: before 10.0.19045.7663 — fixed in 10.0.19045.7663
• Microsoft Windows 11: before 10.0.22631.7517 — fixed in 10.0.22631.7517
• Microsoft Windows 11: before 10.0.26100.9106 — fixed in 10.0.26100.9106
• Microsoft Windows 11 25H2: before 10.0.26200.9106 — fixed in 10.0.26200.9106
• Microsoft Windows 11 version 26H1: before 10.0.28000.2704 — fixed in 10.0.28000.2704
• Microsoft Windows Server 2012: r2
• Microsoft Windows Server 2016: before 10.0.14393.9418 — fixed in 10.0.14393.9418
• Microsoft Windows Server 2019: before 10.0.17763.9115 — fixed in 10.0.17763.9115
• Microsoft Windows Server 2022: before 10.0.20348.5440 — fixed in 10.0.20348.5440
• Microsoft Windows Server 2025: before 10.0.26100.33222 — fixed in 10.0.26100.33222

How to fix

Upgrade to a fixed version: Microsoft Windows 10 1607 10.0.14393.9418; Microsoft Windows 10 10.0.17763.9115; Microsoft Windows 10 10.0.19044.7663; Microsoft Windows 10 10.0.19045.7663; Microsoft Windows 11 10.0.22631.7517; Microsoft Windows 11 10.0.26100.9106; Microsoft Windows 11 25H2 10.0.26200.9106; Microsoft Windows 11 version 26H1 10.0.28000.2704; Microsoft Windows Server 2016 10.0.14393.9418; Microsoft Windows Server 2019 10.0.17763.9115; Microsoft Windows Server 2022 10.0.20348.5440; Microsoft Windows Server 2025 10.0.26100.33222. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68820
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-68820

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