EUVD-2026-22621
GHSA-mvpf-27qc-fjcx
Severity by source
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
6DescriptionCVE.org
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation via use-after-free in Windows Ancillary Function Driver for WinSock (AFD.sys) allows authenticated low-privileged attackers to execute arbitrary code with SYSTEM privileges across all supported Windows versions. Microsoft has released patches for Windows 10 (versions 1607-22H2), Windows 11 (versions 22H3-25H2), and Windows Server (2012-2022 23H2). The vulnerability requires local access and low privileges (PR:L) with high attack complexity (AC:H), but no public exploit
Technical ContextAI
The Windows Ancillary Function Driver for WinSock (AFD.sys) is a kernel-mode driver that provides support for Windows Sockets (Winsock) operations, handling socket creation, I/O operations, and network protocol interfacing at the kernel level. This vulnerability stems from a use-after-free condition (CWE-416), a memory corruption class where the driver references memory after it has been freed, creating a window where an attacker can manipulate the freed memory region. The affected CPE strings indicate broad exposure across the entire Windows ecosystem: Windows 10 builds from version 1607 (released 2016) through 22H2, all Windows 11 versions including the latest 25H2, and Windows Server editions from 2012 through 2022 23H2, encompassing both full GUI and Server Core installations. The kernel-mode nature of AFD.sys means successful exploitation grants complete control over the operating system with SYSTEM-level privileges, bypassing all user-mode security boundaries.
RemediationAI
Vendor-released patches are available through Microsoft's standard update channels and should be applied immediately. Organizations should deploy the following patched builds: Windows 10 Version 1607 and Server 2016 to build 10.0.14393.9060 or later, Windows 10 Version 1809 and Server 2019 to build 10.0.17763.8644 or later, Windows 10 Version 21H2 to build 10.0.19044.7184 or later, Windows 10 Version 22H2 to build 10.0.19045.7184 or later, Windows 11 Versions 22H3 and 23H2 to build 10.0.22631.6936 or later, Windows 11 Version 24H2 to build 10.0.26100.32690 or later, Windows 11 Version 25H2 to build 10.0.26200.8246 or later, Windows Server 2012 to build 6.2.9200.26026 or later, Windows Server 2012 R2 to build 6.3.9600.23132 or later, Windows Server 2022 to build 10.0.20348.5020 or later, and Windows Server 2022 23H2 Edition to build 10.0.25398.2274 or later. Patches can be obtained through Windows Update, Windows Server Update Services (WSUS), Microsoft Update Catalog, or enterprise patch management solutions. Consult the official security
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Same weakness CWE-416 – Use After Free
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External POC / Exploit Code
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