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Windows Server 2016 Windows Server 2016 Security update
Patch Tuesday Zero-day

KB5034767

KB5034767: Cumulative update for Windows Server, version 2016, February 2024. Exploited SmartScreen bypass and critical PGM flaw addressed

In short

The update addresses 34 vulnerabilities, including an actively exploited SmartScreen bypass and a critical PGM remote-code-execution flaw. It also updates Secure Boot certificate support and makes device metadata downloads more secure.

Does it affect you? Applies to: Devices running Windows Server 2016.

Build
14393.6709
Security
34 fixed · 1 critical · 1 exploited

Microsoft publishes separate notes for this KB for Windows 10.

What changes

Improvements 2 changes

UEFI Secure Boot

  • UEFI Secure Boot systems can opt in to use a renewed signing certificate.1
    Adds a renewed signing certificate to the Secure Boot DB variable.

Device metadata

  • Device metadata downloads over HTTPS are more secure.2
    Addresses an issue affecting downloads from Windows Metadata and Internet Services (WMIS) over HTTPS.

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2024-02-13
Type
Cumulative update
VersionBuildChannel
2016 14393.6709 General availability

Security

34 vulnerabilities fixed
1 exploited 1 critical 32 important 1 moderate
VulnerabilitySeverityCVSS
CVE-2024-21351 Exploited
Windows SmartScreen Security Feature Bypass Vulnerability
 Moderate 7.6
CVE-2024-21357
Windows Pragmatic General Multicast (PGM) Remote Code Execution Vulnerability
 Critical 8.1

The table lists the 2 exploited, publicly disclosed or critical vulnerabilities. See all 34 vulnerabilities →

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. This update affects Unified Extensible Firmware Interface (UEFI) Secure Boot systems. It adds a renewed signing certificate to the Secure Boot DB variable. You can now opt for this change. support.microsoft.com
  2. 2. This update addresses an issue that affects the download of device metadata. Downloads from the Windows Metadata and Internet Services (WMIS) over HTTPS are now more secure. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 2 quoted passages · compared with Microsoft's page on Nov 8, 2026
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: not passed

A second AI read the text against the sources: correctness 5/5, clarity 4/5, completeness 5/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake