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Windows 10 1607 Windows 10 1607 Security update
Patch Tuesday Zero-day

KB5075999

KB5075999: Cumulative update for Windows 10, version 1607, February 2026. Exploited Shell and MSHTML flaws patched; GPU stability fixed

In short

The update fixes 20 vulnerabilities, including two publicly disclosed and exploited Shell and MSHTML security bypasses, and resolves a stability issue on some GPU configurations.

Does it affect you? Applies to: Devices running Windows 10 Enterprise LTSB 2016, version 1607.

Build
14393.8868
Security
20 fixed · 5 exploited
Restart
Required

Microsoft publishes separate notes for this KB for Windows Server.

What changes

Fix 1 change

Graphics

For: devices with certain GPU configurations

  • A stability issue affecting some GPU configurations is fixed.1

Technical details

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

Data sheet

Released
2026-02-10
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5073722, KB5074974, KB5071543, KB5068864
+14 earlier KB5066836, KB5065427, KB5063871, KB5062560, KB5061010, KB5058383, KB5058921, KB5055521, KB5053594, KB5052006, KB5049993, KB5048671, KB5046612, KB5037423
Replaced by
KB5078938
VersionBuildChannel
1607 14393.8868 General availability

Security

20 vulnerabilities fixed
5 exploited 19 important 1 moderate
VulnerabilitySeverityCVSS
CVE-2026-21510 Exploited
Windows Shell Security Feature Bypass Vulnerability
 Important 8.8
CVE-2026-21513 Exploited
MSHTML Framework Security Feature Bypass Vulnerability
 Important 8.8
CVE-2026-21519 Exploited
Desktop Window Manager Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-21533 Exploited
Windows Remote Desktop Services Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-21525 Exploited
Windows Remote Access Connection Manager Denial of Service Vulnerability
 Moderate 6.2
CVE-2026-21255
Windows Hyper-V Security Feature Bypass Vulnerability
 Important 8.8
CVE-2026-21231
Windows Kernel Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-21236
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-21238
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-21239
Windows Kernel Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-21246
Windows Graphics Component Elevation of Privilege Vulnerability
 Important 7.8
CVE-2026-20846
GDI+ Denial of Service Vulnerability
 Important 7.5
CVE-2026-21235
Windows Graphics Component Elevation of Privilege Vulnerability
 Important 7.3
CVE-2026-21244
Windows Hyper-V Remote Code Execution Vulnerability
 Important 7.3
CVE-2026-21247
Windows Hyper-V Remote Code Execution Vulnerability
 Important 7.3
CVE-2026-21248
Windows Hyper-V Remote Code Execution Vulnerability
 Important 7.3
CVE-2026-21253
Mailslot File System Elevation of Privilege Vulnerability
 Important 7.0
CVE-2026-21508
Windows Storage Elevation of Privilege Vulnerability
 Important 7.0
CVE-2026-21222
Windows Kernel Information Disclosure Vulnerability
 Important 5.5
CVE-2026-21249
Windows NTLM Spoofing Vulnerability
 Important 3.3

Updated components

1,123 files changed since the previous update for the same versions.

Top changed componentsFiles
Graphics and display26
Networking26
Bluetooth18
Remote Desktop17
Security and sign-in14
Hyper-V and virtualization13
File Explorer and shell10
Search10
Settings10
Storage and file systems10
Kernel8
Secure Boot8

Sources

Updated
Cited passages from Microsoft's official notes (1)
  1. 1. Fixed: A stability issue affecting certain graphics processing units (GPUs) configurations. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 1 quoted passage · 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 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