The Update BureauKB5065427: Cumulative update for Windows 10, version 1607, September 2025. Critical Hyper-V flaw patched; MSI repair prompts reduced
Fixes five critical security flaws, including a Hyper-V remote code execution vulnerability, and reduces unexpected UAC prompts during some MSI repairs.
Does it affect you? Applies to: Windows 10, version 1607; the update page lists Windows 10 IoT Enterprise 2016 LTSB under “Applies to.”
Review notes Additional details from the official release notes (1) Read note
- In detail Windows 10 support ended on October 14, 2025. Microsoft says it will no longer provide free Windows Update software updates, technical assistance, or security fixes after that date, and recommends moving to Windows 11.
The official sources are linked at the end of the page.
Microsoft publishes separate notes for this KB for Windows Server.
What changes
Fix 1 change
App compatibility (known issue)
For: Non-admin users and IT administrators
-
Non-admin users get fewer unexpected UAC prompts when certain apps run installation or repair actions.1
Reduces the scope for UAC prompts during certain MSI custom actions, including configuration or repair operations in the foreground or background. IT admins can add specific apps to an allowlist to disable prompts for them.
New feature 1 change
File Server
-
IT teams can check whether devices and software are compatible with SMB Server security measures before deploying them.2
Enables auditing SMB client compatibility for SMB Server signing and SMB Server EPA.
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2025-09-09
- Classification
- Security Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5063871, KB5062560, KB5061010, KB5058383
- Replaced by
- KB5066836
| Version | Build | Channel |
|---|---|---|
| 1607 | 14393.8422 | General availability |
Security
| Vulnerability | Severity | CVSS |
|---|---|---|
|
Windows NTLM Elevation of Privilege Vulnerability
|
Critical | 8.8 |
|
Windows Graphics Component Elevation of Privilege Vulnerability
|
Critical | 7.8 |
|
Windows Hyper-V Remote Code Execution Vulnerability
|
Critical | 6.7 |
|
Graphics Kernel Remote Code Execution Vulnerability
|
Critical | 6.7 |
|
Windows Imaging Component Information Disclosure Vulnerability
|
Critical | 5.5 |
|
Windows SMB Elevation of Privilege Vulnerability
|
Important | 8.8 |
The table lists the 6 exploited, publicly disclosed or critical vulnerabilities. See all 35 vulnerabilities →
Downloads (Microsoft Update Catalog)
Updated components
550 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| Graphics and display | 14 |
| Networking | 14 |
| Security and sign-in | 12 |
| Remote Desktop | 11 |
| Secure Boot | 11 |
| Kernel | 9 |
| Search | 8 |
| File Explorer and shell | 6 |
| Hyper-V and virtualization | 6 |
| Settings | 4 |
| Storage and file systems | 4 |
Sources
Cited passages from Microsoft's official notes (2)
-
1.
Fixed: Addresses an issue that caused non-admin users to receive unexpected User Account Control (UAC) prompts when MSI installers perform certain
support.microsoft.com -
2.
This update enables auditing SMB client compatibility for SMB Server signing as well as SMB Server EPA.
support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 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 3/5. 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