Skip to the content
The Update Bureau
Windows Server 2019 Windows Server 2019 Security update
Patch Tuesday

KB5063877

KB5063877: Cumulative update for Windows Server, version 2019, August 2025. GDI+ remote-code flaw fixed; BitLocker cluster restarts stopped

In short

Fixes 54 vulnerabilities, including three critical flaws, and stops repeated Cluster Service failures on BitLocker configurations using Cluster Shared Volumes.

Does it affect you? Applies to: Devices running Windows Server 2019, all supported editions.

Build
17763.7678
Security
54 fixed · 3 critical
Restart
Required

Microsoft publishes separate notes for this KB for Windows 10.

What changes

Fixes 2 changes

Cluster Service

For: Servers using BitLocker with Cluster Shared Volumes

  • The Cluster Service no longer repeatedly stops and restarts on the affected servers, preventing cluster nodes from failing to rejoin or entering quarantine and virtual machines from restarting repeatedly.1
    Fixes the issue on configurations using BitLocker with Cluster Shared Volumes (CSV), which could also produce frequent Event ID 7031 errors.

Input and Composition

For: Users of the Microsoft Changjie Input Method

  • Users can select words again with the Microsoft Changjie Input Method.2

Improvement 1 change

Servicing stack

  • The component that installs Windows updates gets reliability improvements that help mitigate potential problems during installation.3
    Includes the servicing stack update KB5062800, build 17763.7557, combined with the latest cumulative update.

Known issues

  1. Resolved Affects: Everyone Resolved by KB5065428

    Unexpected User Account Control (UAC) prompt when doing MSI repair operations

    After installing the update, standard users might see a User Account Control prompt during MSI repair operations or certain app installations. Silent MSI repairs by non-admin users might fail; for example, Office Professional Plus 2010 can fail with Error 1730. Updates released on and after September 9, 2025 (KB5065428) resolve this issue.4

    Resolution Fixed in KB5065428

    Install KB5065428 (or a later cumulative update) on affected devices. No manual workaround is required after updating.

Technical details

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

Data sheet

Released
2025-08-12
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5062557, KB5060531, KB5061978, KB5058392
+4 earlier KB5059091, KB5058922, KB5050008, KB5037425
Replaced by
KB5066187
VersionBuildChannel
2019 17763.7678 General availability

Security

54 vulnerabilities fixed
3 critical 51 important
VulnerabilitySeverityCVSS
CVE-2025-53766
GDI+ Remote Code Execution Vulnerability
 Critical 9.8
CVE-2025-53778
Windows NTLM Elevation of Privilege Vulnerability
 Critical 8.8
CVE-2025-50177
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
 Critical 8.1

The table lists the 3 exploited, publicly disclosed or critical vulnerabilities. See all 54 vulnerabilities →

Downloads (Microsoft Update Catalog)

x64 2019
704.9 MB
windows10.0-kb5063877-x64.msu Main update · KB5063877 SHA-1: 3e569e4b…d6b153

Updated components

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

Top changed componentsFiles
Bluetooth17
Graphics and display11
Hyper-V and virtualization7
Secure Boot7
Security and sign-in7
Kernel5
Networking5
Audio1
File Explorer and shell1
Remote Desktop1
Storage and file systems1

Sources

Updated
Cited passages from Microsoft's official notes (4)
  1. 1. [Cluster Service] Fixed: A known issue affecting Windows Server 2019 where the Cluster Service would repeatedly stop and restart. This behavior caused nodes to fail to rejoin the cluster or enter quarantine support.microsoft.com
  2. 2. [Input and Composition] Fixed: A known issue with the Microsoft Changjie Input Method. Users were unable to select words after a recent update. support.microsoft.com
  3. 3. SSUs improve the reliability of the update process to mitigate potential issues while installing updates. support.microsoft.com
  4. 4. This issue is resolved by Windows updates released on and after September 9, 2025 (KB5065428). support.microsoft.com
Checked automatically: 8 of 8 checks passed, 4 quoted passages · compared with Microsoft's page on Oct 20, 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: 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