Remote Desktop Client Remote Code Execution Vulnerability

Heap-based buffer overflow in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

Read the vendor bulletin Get alerts for Windows Server 2025 (Server Core installation)

9.8CVSS out of 10High severity

Scope

What the vendor says is affected

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 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems

Versions the vendor lists as fixed

10.0.26100.33158
10.0.26200.8875
10.0.26100.8875
10.0.28000.2525

Next step

What the vendor recommends

Install KB5099536. Install KB5101650. Install KB5101649.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

Jul 14, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Sep 8, 2026 at 7:00 AM UTC
Updated by Microsoft Security Response Center
The vendor changed the advisory after it was first published.
Sep 28, 2026 at 11:20 AM UTC
Added to SecurityAlert
We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2026-54990View CVSS, KEV, EPSS, and threat context

Source

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Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-54990
Last source check: Sep 28, 2026 at 11:20 AM UTC

Open the official bulletin How SecurityAlert builds this record

Your environment

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Watch Windows Server 2025 (Server Core installation)

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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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