IRONSMITHINTEL
HIGH
|Auth: varies by cve|Reboot: required|Est. 30–60 minutes including reboot|Manual only

KB5005030: Windows Server 2016 Cumulative Update (August 2021)

The August 2021 Patch Tuesday cumulative update for Windows Server 2016 addresses 44 security vulnerabilities including elevation of privilege and remote code execution flaws.

Published Aug 10, 2021 · Updated May 10, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

Attackers targeting unpatched Windows Server 2016 systems can exploit the vulnerabilities addressed in KB5005030 for privilege escalation, lateral movement, and in some cases remote code execution. Servers missing multiple monthly updates accumulate multiple unpatched attack paths simultaneously.

How the attack works

KB5005030 bundles all security fixes for Windows Server 2016 since the July 2021 cumulative update. It addresses vulnerabilities across the Windows kernel, networking stack, print spooler, and Remote Desktop services. Cumulative updates must be applied as a complete package.

Am I affected?Quick check

Probably yes if any of these apply:

All Windows Server 2016 systems
Running Windows Server 2016 prior to KB5005030

Affected OS versions

Windows Server 2016
Fixed inKB5005030
Real-world incidentsWhat we've seen

An organisation running automated vulnerability scans identifies a cluster of Windows Server 2016 systems missing the August 2021 update. The missing patches include a privilege escalation vulnerability in the Windows kernel that has a public PoC. The exposure window between Patch Tuesday and the organisation's 30-day patching SLA creates unnecessary risk.

How to patch

Manual download

For air-gapped servers or out-of-band deployment. Microsoft Update Catalog returns every OS-version variant of this update.

↗ Microsoft Update CatalogKB5005030

Manual remediation steps

30–60 minutes including reboot

Check if KB5005030 is Installed

Get-HotFix -Id KB5005030
# No output = patch not installed

Apply via Windows Update

1
Open Settings → Windows Update
2
Click Check for updates
3
Install all available updates
4
Restart when prompted

Apply Manually

1
Download KB5005030 from https://catalog.update.microsoft.com
2
Run the MSU installer as Administrator
3
Restart the server

Apply via WSUS / SCCM

Approve KB5005030 in your patch management console.

Verify

Get-HotFix -Id KB5005030
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