Microsoft Security Response CenterCVE-2026-33826

Windows Active Directory Remote Code Execution Vulnerability

Improper input validation in Windows Active Directory allows an authorized attacker to execute code over an adjacent network.

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8.0CVSS out of 10Critical severity

Scope

What the vendor says is affected

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 2022, 23H2 Edition (Server Core installation)
Windows Server 2025
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

10.0.17763.8644
10.0.20348.5020
10.0.26100.32690
10.0.25398.2274
10.0.14393.9060
6.3.9600.23132

Next step

What the vendor recommends

Install KB5082123. Install KB5082142. Install KB5082063. Install KB5082060. Install KB5082198. Install KB5082126.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

Apr 14, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Sep 27, 2026 at 11:11 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2026-33826View CVSS, KEV, EPSS, and threat context

Source

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Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-33826
Last source check: Sep 27, 2026 at 11:11 PM UTC

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Your environment

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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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