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Windows Server 2022 Windows Server 2022 Security update
Patch Tuesday

KB5078766

KB5078766: Cumulative update for Windows Server, version 2022, March 2026. Secure Boot certificate targeting expands; catalog selection gets safer

In short

The update fixes 40 Important-severity vulnerabilities and improves Secure Boot certificate targeting and trusted catalog selection in Windows System Image Manager.

Does it affect you? Applies to: Devices running Windows Server 2022. The update is available for x64 systems.

Build
20348.4893
Security
40 fixed
Restart
Required
Review notes Additional details from the official release notes (1) Read note
  • What to do WSUS automatically syncs this update when Product is set to Microsoft Server operating system-21H2 and Classification to Security Updates.

The official sources are linked at the end of the page.

What changes

Improvements 3 changes

Secure Boot

Gradual rollout Verified in package

For: Devices eligible for automatic Secure Boot certificate updates

  • Eligible devices are more likely to receive new Secure Boot certificates automatically. Servers are unlikely to qualify.1
    Targeting uses primarily client device diagnostic data; servers are not explicitly excluded. Certificate delivery is phased and depends on sufficient successful update signals.

Windows System Image Manager

For: Windows System Image Manager users

  • A warning helps you confirm that a catalog file you select comes from a trusted source.2
    Improves the reliability of choosing trusted catalog files.

Servicing stack

  • The component that installs Windows updates receives quality improvements to help devices receive and install updates reliably.3
    Includes servicing stack update KB5078763, build 20348.4880.

Known issues

  1. Open Affects: Organizations and IT administrators

    Windows Server Update Services (WSUS) does not display error details

    After KB5070884 or later updates, Windows Server Update Services (WSUS) does not display synchronization error details. This functionality is temporarily removed to address CVE-2025-59287.4

    Workaround status No workaround yet

    Microsoft has not published a manual workaround for this issue yet. Monitor release health until a resolving update is available.

Technical details

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

Data sheet

Released
2026-03-10
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5082314, KB5075906, KB5078136, KB5077800
+33 earlier KB5073457, KB5071547, KB5068787, KB5070884, KB5066782, KB5065432, KB5063880, KB5062572, KB5060526, KB5061906, KB5058385, KB5059092, KB5058920, KB5055526, KB5053603, KB5051979, KB5052819, KB5049983, KB5048654, KB5046616, KB5047767, KB5044281, KB5042881, KB5041160, KB5040437, KB5041054, KB5039227, KB5037782, KB5036909, KB5037422, KB5035857, KB5034770, KB5034129
Replaced by
KB5082142
VersionBuildChannel
2022 20348.4893 General availability

Security

40 vulnerabilities fixed
40 important
VulnerabilitySeverityCVSS

The table lists the 0 exploited, publicly disclosed or critical vulnerabilities. See all 40 vulnerabilities →

Downloads (Microsoft Update Catalog)

x64 2022
499.4 MB
windows10.0-kb5078766-x64.msu Main update · KB5078766 SHA-1: 97ad62f0…cc0925

Updated components

556 files changed since the previous update for the same versions.

Top changed componentsFiles
File Explorer and shell10
Graphics and display10
Networking6
Secure Boot6
Kernel4
Storage and file systems4
Hyper-V and virtualization3
Windows Update3
Remote Desktop2
Search2
Security and sign-in2
Settings2

Verified in package: changed files confirm Secure Boot.

Sources

Updated
Cited passages from Microsoft's official notes (4)
  1. 1. [Secure Boot] With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. support.microsoft.com
  2. 2. [Windows System Image Manager] Improved: This update improves the reliability of choosing trusted catalog files. It adds a warning dialog that helps you confirm that the file you select comes from a trusted source. support.microsoft.com
  3. 3. This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. support.microsoft.com
  4. 4. After installing KB5070884 or later updates, Windows Server Update Services (WSUS) does not display synchronization error details within its error reporting. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 4 quoted passages · compared with Microsoft's page on Sep 25, 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 4/5, clarity 5/5, completeness 4/5. 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