Description
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Published: 2026-05-12
Score: 7 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The Windows Ancillary Function Driver for WinSock contains a use‑after‑free flaw that can be triggered by an authorized local user. Exploitation of this bug bypasses the intended authority boundaries and can grant SYSTEM‑level access. The weakness is a classic use‑after‑free vulnerability (CWE‑416) that undermines memory safety within the driver and allows the attacker to execute arbitrary code with elevated privileges.

Affected Systems

Affected installations include Microsoft Windows 10 editions from version 1607 through 22H2, Windows 11 releases 23H2, 24H2, 25H2, 22H3, and 26H1, and the Windows Server line from 2012 through 2025 as well as the 23H2 edition. All of these systems run the AFD component for WinSock and therefore are susceptible to the privilege‑escalation condition described.

Risk and Exploitability

The CVSS score of 7.0 indicates a high impact severity, while the EPSS is currently unavailable and the vulnerability is not listed in CISA's KEV catalog, suggesting that there has been no confirmed exploitation yet. An attacker would need local access and sufficient privileges to invoke WinSock functions that exercise the freed memory region; once achieved, the compromised process could acquire SYSTEM rights. Because this is a local privilege‑escalation scenario, the practical risk depends on the attacker’s initial foothold, but the ability to reach full control of the host makes it a high‑priority issue for internal security teams.

Generated by OpenCVE AI on May 12, 2026 at 19:32 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the Microsoft security update that fixes CVE‑2026‑35416 as published in the MSRC update guide.
  • Reboot the system after the update to load the corrected Windows Ancillary Function Driver and ensure the AFD component is running the patched build.
  • If the patch cannot be applied immediately, restrict WinSock usage for local users or enforce least‑privilege accounts to limit the opportunity for exploitation.

Generated by OpenCVE AI on May 12, 2026 at 19:32 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 12 May 2026 17:30:00 +0000

Type Values Removed Values Added
Description Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Title Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
Weaknesses CWE-416
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_23h2:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
References
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}


Subscriptions

Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1 Windows Server 2012 Windows Server 2012 R2 Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025 Windows Server 23h2
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-05-13T03:57:08.945Z

Reserved: 2026-04-02T19:21:11.804Z

Link: CVE-2026-35416

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-12T18:17:11.940

Modified: 2026-05-12T18:17:11.940

Link: CVE-2026-35416

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-12T19:45:15Z

Weaknesses