KB5063878: Cumulative update for Windows 11, version 24H2, August 2025. Critical graphics flaws and new-device sign-in delays addressed

Critical graphics and other security flaws are addressed, along with delays when signing in on new devices. Secure Boot certificates need attention before they expire.

Does it affect you? Applies to: Devices running Windows 11, version 24H2, on x64 or Arm64 processors.

Review notes Additional details from the official release notes (2) Read notes

Known issues KB5065426 addresses the NDI streaming performance issue.
Known issues KB5065426 addresses the unexpected UAC prompt issue during MSI repair and related operations.

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

Microsoft publishes separate notes for this KB for Windows Server.

What changes

Improvements 2 changes

AI components

Verified in package

AI components are updated on Copilot+ PCs.¹
Image Search, Content Extraction, Semantic Analysis, and Settings Model are updated to version 1.2507.797.0.

Servicing stack

The component that installs Windows updates receives quality improvements.²
Includes servicing stack update KB5065381, build 26100.4933.

Fix 1 change

Authentication

Sign-in delays on some new devices caused by preinstalled packages are addressed.³

Known issues

Open Affects: Everyone

Network Device Interface streaming performance issue

NDI streaming between PCs can have delays or uneven audio and video after this update. This can affect OBS Studio and NDI Tools, especially when Display Capture is enabled on the source PC.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.
Open Affects: Everyone

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

Standard users might see an unexpected UAC prompt during MSI repair and related tasks, such as opening some Autodesk apps or installing per-user apps.⁵

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.
Open Affects: Everyone

Error events are logged for CertificateServicesClient

CertificateServicesClient error 57 can appear each time the device restarts, but it does not affect Windows. KB5064081 addresses the event.⁶

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.
Open Affects: Organizations and IT administrators

Install error with error code 0x80240069

Devices managed through WSUS might have failed to install this update with error 0x80240069. Microsoft says the issue is resolved.⁷

How to apply the workaround Workaround

If this happened, refresh and re-sync with WSUS to install the update.⁷

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: KB5062660, KB5064489, KB5062553, KB5060829

+27 earlier
KB5063060, KB5060842, KB5058499, KB5061977, KB5058411, KB5055627, KB5059087, KB5055523, KB5053656, KB5053598, KB5052093, KB5051987, KB5050094, KB5050009, KB5048667, KB5046740, KB5046617, KB5044384, KB5044284, KB5043178, KB5043080, KB5041865, KB5041571, KB5040529, KB5040435, KB5039304, KB5039239
Replaced by: KB5065426

Version	Build	Channel
24H2	26100.4946	General availability

Security

49 vulnerabilities fixed

5 critical 44 important

Vulnerability	Severity	CVSS
CVE-2025-50165 Windows Graphics Component Remote Code Execution Vulnerability	Critical	9.8
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
CVE-2025-50176 DirectX Graphics Kernel Remote Code Execution Vulnerability	Critical	7.8

The table lists the 5 exploited, publicly disclosed or critical vulnerabilities. See all 49 vulnerabilities →

Downloads (Microsoft Update Catalog)

x64 24H2

3.0 GB

windows11.0-kb5063878-x64.msu Main update · KB5063878 SHA-1: c2d51482…66896d windows11.0-kb5043080-x64.msu Prerequisite · KB5043080 SHA-1: 95344967…9c83e8

Arm64 24H2

3.4 GB

windows11.0-kb5063878-arm64.msu Main update · KB5063878 SHA-1: fff01cb6…ee8b88 windows11.0-kb5043080-arm64.msu Prerequisite · KB5043080 SHA-1: df540a05…0f090b

Updated components

1,100 files changed since the previous update for the same versions.

Top changed components	Files
Graphics and display	27
Remote Desktop	12
Search	12
Printing	11
File Explorer and shell	10
Secure Boot	6
Security and sign-in	6
Storage and file systems	6
Emoji and input	5
Kernel	5
Networking	5
Settings	4

Verified in package: changed files confirm AI components.

Sources

Microsoft Support: KB5063878

Updated Nov 7, 2026

Cited passages from Microsoft's official notes (7)

1. This release updates the following AI components: support.microsoft.com
2. This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. support.microsoft.com
3. [Authentication] Fixed: This update addresses an issue that caused delays during sign-in on new devices. The delay was due to certain preinstalled packages. support.microsoft.com
4. After installing the August 2025 Windows security update (KB5063878), you might experience delays or uneven audio and video performance when using Network Device Interface (NDI) to stream or transfer feeds between PCs. support.microsoft.com
5. After installing the update, standard users might see a User Account Control (UAC) prompt in several scenarios. support.microsoft.com
6. This issue is addressed in KB5064081. support.microsoft.com
7. The issue affecting the Windows Update service for devices managed through Windows Server Update Services (WSUS) has been resolved. If you experienced this problem, refresh, and re-sync with WSUS to install this update. support.microsoft.com

Checked automatically: 8 of 8 checks passed, 7 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 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