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Windows Server 2019 Windows Server 2019 Security update
Patch Tuesday

KB5050008

KB5050008: Cumulative update for Windows Server, version 2019, January 2025. Critical OLE and Remote Desktop flaws patched; driver blocklist expanded

In short

Fixes 118 vulnerabilities, including 8 Critical flaws across several Windows components. It also adds vulnerable drivers to the blocklist to help guard against BYOVD attacks.

Does it affect you? Applies to: Devices running Windows Server 2019, x64.

Build
17763.6775
Security
118 fixed · 8 critical
Restart
Required

Microsoft publishes separate notes for this KB for Windows 10.

What changes

Improvements 2 changes

Windows Kernel Vulnerable Driver Blocklist file (DriverSiPolicy.p7b)

Verified in package
  • The list of drivers considered at risk of BYOVD attacks grows.1
    Adds drivers to DriverSiPolicy.p7b.

Servicing stack

For: Windows Server 2019 devices

  • The component that installs Windows updates receives quality improvements.2
    Includes servicing stack update KB5050110, build 17763.6763.

Known issues

  1. Resolved Affects: Organizations and IT administrators Resolved by KB5053596

    Following the installation of the October 2024 security update, some customers report that the OpenSSH (Open Secure Shell) service fails to start, preventing SSH connections.

    The OpenSSH service issue reported after the October 2024 security update, which can prevent SSH connections, is addressed by KB5053596.3

    Resolution Fixed in KB5053596

    Install KB5053596 (or a later cumulative update) on affected devices. No manual workaround is required after updating.

  2. Resolved Affects: Organizations and IT administrators

    Devices that have certain Citrix components installed might be unable to complete installation of the January 2025 Windows security update.

    Devices with Citrix Session Recording Agent version 2411 might fail to complete the January 2025 update installation and revert changes on restart. Citrix Session Recording Agent version 2503 and newer resolve the issue.4

    Resolution Resolved

    Microsoft has resolved this issue in a subsequent update. No manual workaround is required after updating.

  3. Resolved Affects: Everyone Resolved by KB5052000

    After installing this security update, you might experience issues with USB audio devices.

    USB audio devices might stop working, especially when the audio setup uses a USB 1.0 audio-driver-based DAC. KB5052000 addresses the issue.5

    Resolution Fixed in KB5052000

    Install KB5052000 (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
2025-01-14
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5037425
Replaced by
KB5058922
VersionBuildChannel
2019 17763.6775 General availability

Security

118 vulnerabilities fixed
8 critical 110 important
VulnerabilitySeverityCVSS
CVE-2025-21298
Windows OLE Remote Code Execution Vulnerability
 Critical 9.8
CVE-2025-21307
Windows Reliable Multicast Transport Driver (RMCAST) Remote Code Execution Vulnerability
 Critical 9.8
CVE-2024-49120
Windows Remote Desktop Services Remote Code Execution Vulnerability
 Critical 8.1
CVE-2025-21294
Microsoft Digest Authentication Remote Code Execution Vulnerability
 Critical 8.1
CVE-2025-21295
SPNEGO Extended Negotiation (NEGOEX) Security Mechanism Remote Code Execution Vulnerability
 Critical 8.1
CVE-2025-21297
Windows Remote Desktop Services Remote Code Execution Vulnerability
 Critical 8.1
CVE-2025-21309
Windows Remote Desktop Services Remote Code Execution Vulnerability
 Critical 8.1
CVE-2025-21296
BranchCache Remote Code Execution Vulnerability
 Critical 7.5
CVE-2025-21308
Windows Themes Spoofing Vulnerability
 Important 6.5

The table lists the 9 exploited, publicly disclosed or critical vulnerabilities. See all 118 vulnerabilities →

Downloads (Microsoft Update Catalog)

x64 2019
686.0 MB
windows10.0-kb5050008-x64.msu Main update · KB5050008 SHA-1: 80eb33a0…9bb6c9

Updated components

1,747 files changed since the previous update for the same versions.

Top changed componentsFiles
Networking16
Hyper-V and virtualization15
Remote Desktop13
Security and sign-in13
Secure Boot11
Graphics and display8
Printing8
File Explorer and shell7
Storage and file systems7
Kernel6
Search5
Audio4

Verified in package: changed files confirm Windows Kernel Vulnerable Driver Blocklist file (DriverSiPolicy.p7b).

Sources

Updated
Cited passages from Microsoft's official notes (5)
  1. 1. This update adds to the list of drivers that are at risk for Bring Your Own Vulnerable Driver (BYOVD) attacks. support.microsoft.com
  2. 2. This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. support.microsoft.com
  3. 3. This issue is addressed in KB5053596. support.microsoft.com
  4. 4. Devices that have certain Citrix components installed might be unable to complete installation of the January 2025 Windows security update. support.microsoft.com
  5. 5. After installing this security update, you might experience issues with USB audio devices. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 5 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: not passed

A second AI read the text against the sources: correctness 5/5, clarity 5/5, 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