Microsoft Security Response CenterCVE-2026-61920

Windows DNS Server Remote Code Execution Vulnerability

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows DNS allows an authorized attacker to execute code over a network.

Read the vendor bulletin Get alerts for Windows

6.6CVSS out of 10High severity

Scope

What the vendor says is affected

Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows Server 2025 (Server Core installation)
Windows Server 2025
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows Server 2012 R2
Windows Server 2012 R2 (Server Core installation)

Versions the vendor lists as fixed

10.0.17763.9121
10.0.20348.5499
10.0.20348.5440
10.0.26100.33296
10.0.26100.33222
10.0.28000.2704
10.0.14393.9418
6.3.9600.23338

Next step

What the vendor recommends

Install KB5120238. Install KB5120242. Install KB5120229. Install KB5120233. Install KB5120228. Install KB5121000. Install KB5120418. Install KB5120385.

Review the complete instructions on the vendor's site

Update history

What changed in later vendor updates

SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.

Aug 20, 2026 at 7:00 PM UTC
- The vendor changed its remediation guidance.

Timeline

When this advisory changed

Aug 11, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Aug 20, 2026 at 6:50 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Sep 2, 2026 at 5:15 PM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory

CVE-2026-61920View CVSS, KEV, EPSS, and threat context

Source

Start with the vendor's bulletin

SecurityAlert organizes the fields the vendor published. The original bulletin remains the source of record for affected versions, fixes, and later changes.

Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-61920
Last source check: Sep 13, 2026 at 2:40 AM UTC

Open the official bulletin How SecurityAlert builds this record

Your environment

Check the systems you actually run

A vendor advisory can tell you what may be affected. It cannot tell you whether that product and version are installed in your environment.

Confirm the product and installed version.
Read the vendor's prerequisites and exceptions.
Test the update or mitigation through your normal change process.

Watch Windows

Keep following

Get new Microsoft Security Response Center advisories

Use the vendor-specific RSS feed or set up alerts for a product your team relies on.

Follow this vendor's RSS feed

What the vendor says is affected

Versions the vendor lists as fixed

What the vendor recommends

What changed in later vendor updates

When this advisory changed

CVEs named in this advisory

Related advisories from Microsoft Security Response Center

Virtual Hard Disk (VHD) Miniport Driver Remote Code Execution Vulnerability

Windows DHCP Server Denial of Service Vulnerability

DirectWrite Remote Code Execution Vulnerability

Windows Work Folder Service Remote Code Execution Vulnerability

Windows Imaging Component Remote Code Execution Vulnerability

Windows Link Layer Topology Discovery Protocol Remote Code Execution Vulnerability