Microsoft Security Response CenterCVE-2026-24293

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

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

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7.8CVSS out of 10High severity

Scope

What the vendor says is affected

Windows 11 Version 26H1 for ARM64-based Systems
Windows 11 version 26H1 for x64-based Systems
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows 10 Version 21H2 for 32-bit Systems
Windows 10 Version 21H2 for ARM64-based Systems
Windows 10 Version 21H2 for x64-based Systems
Windows 10 Version 22H2 for x64-based Systems
Windows 10 Version 22H2 for ARM64-based Systems
Windows 10 Version 22H2 for 32-bit Systems
Windows Server 2025 (Server Core installation)
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 23H2 for ARM64-based Systems
Windows 11 Version 23H2 for x64-based Systems
Windows Server 2022, 23H2 Edition (Server Core installation)
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025

Versions the vendor lists as fixed

10.0.28000.1719
10.0.20348.4893
10.0.20348.4830
10.0.19044.7058
10.0.19045.7058
10.0.26100.32522
10.0.26100.32463
10.0.26200.8037
10.0.26200.7979
10.0.22631.6783
10.0.25398.2207
10.0.26100.8037
10.0.26100.7979

Next step

What the vendor recommends

Install KB5079466. Install KB5078766. Install KB5078737. Install KB5078885. Install KB5078740. Install KB5078736. Install KB5079473. Install KB5079420. Install KB5078883. Install KB5078734.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

Mar 10, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
May 29, 2026 at 7:00 AM UTC
Updated by Microsoft Security Response Center
The vendor changed the advisory after it was first published.
Oct 2, 2026 at 12:40 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Oct 3, 2026 at 1:00 PM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory

CVE-2026-24293View CVSS, KEV, EPSS, and threat context

Source

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Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-24293
Last source check: Oct 3, 2026 at 1:00 PM UTC

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What the vendor says is affected

Versions the vendor lists as fixed

What the vendor recommends

When this advisory changed

CVEs named in this advisory

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