The Update Bureau
Monthly security update
- Version 26H1 28000.2525 KB5101649 → 26H1
- Version 24H2 / 25H2 26100.8875 KB5101650 → 24H2, 25H2
- Version 23H2 22631.7376 KB5099414 → 23H2
Release volume
61
updates released
19 more than June (42), vs 50/mo in 2026.
Security flaws fixed
537
vulnerabilities
+303 flaws compared to June (234).
Critical & urgent
43
critical · 3 zero-days
34 critical in June, plus 1 out-of-band release this month .
2026 Year-to-Date Trend
1,210 security flaws fixed across 353 updates in 2026
97 critical flaws and 12 exploited zero-days patched across the 7 published months of 2026.
Distinct security flaws fixed per month
Jan – Jul 2026
Monthly security update
- Version 21H2 / 22H2 19044.7548 KB5099539 → 21H2, 22H2
- Version 1809 17763.9020 KB5099538 → 1809
- Version 1607 14393.9339 KB5099535 → 1607
Monthly security update
- Version 2025 26100.33158 KB5099536 → 2025
- Version 2022 20348.5386 KB5099540 → 2022
- Version 2019 17763.9020 KB5099538 → 2019
- Version 2016 14393.9339 KB5099535 → 2016
Monthly security update
- .NET 3.5 / 4.8.1 · Windows 11 26H1 KB5101002 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 25H2, Windows Server 2025 KB5100998 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 24H2 KB5101001 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 23H2 KB5101004 → 3.5, 4.8.1
+7 more
KB5101000 3.5, 4.8.1 · KB5101005 3.5, 4.8.1 · KB5101006 3.5, 4.8 · KB5101010 3.5, 4.8 · KB5101008 3.5, 4.8 · KB5101007 4.8 · KB5100989 3.5, 4.7.2
Monthly security update
- Version CU6 + GDR 17.0.4060.2 KB5101346 → 2025
- Version GDR 17.0.1125.2 KB5102333 → 2025
- Version CU25 + GDR 16.0.4262.2 KB5101347 → 2022
- Version GDR 16.0.1190.2 KB5102334 → 2022
+6 more
KB5102335 2019 · KB5102336 2019 · KB5102337 2017 · KB5102338 2017 · KB5102339 2016 · KB5102340 2016
Monthly security update
- Subscription Edition (SE) 16.0.19725.20434 KB5002882 → SE
- Version 2019 16.0.10417.20175 KB5002883 → 2019
- Version 2016 16.0.5561.1001 KB5002891 → 2016
Monthly security update
- Office Online Server 16.0.10417.20175 KB5002884 → OOS
Monthly security update
- Version RTM 15.2.2562.45 KB5103212 → SE
- Version CU15 · ESU only 15.2.1748.48 KB5103213 → 2019
- Version CU14 · ESU only 15.2.1544.43 KB5103214 → 2019
- Version CU23 · ESU only 15.1.2507.71 KB5103215 → 2016
Vulnerabilities fixed, by version
All updates
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Windows 11 · Future platformsWindows 11 Windows 11 Insider Future platforms Insider PreviewExperimental ChannelBuild 29639.1000
Longer update pauses, gamepad settings, and smart-card disconnects
Experimental Channel build 29639.1000 gradually adds repeatable update-pause extensions, gamepad navigation for Bluetooth settings, and smart-card removal controls for remote sessions.
Changes 3 improved -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28120.2630
Touchpad gesture controls and network backup fixes
Adds touchpad gesture options, changes update and hibernation behavior, and fixes several backup, File Explorer, and input issues.
Changes 4 new · 4 improved · 3 fixes -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewBeta ChannelBuild 28020.2623
Taskbar position options and SMB File History backup fix
Adds taskbar position and size choices, touchpad gesture controls, and Windows Update changes. It also fixes File History backups to network shares and a File Explorer preview issue.
Changes 4 new · 2 improved · 2 fixes -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewExperimental ChannelBuild 26300.9032
Activity-based Search indexing and a Start menu crash fix
Adds activity-based file indexing in Search and fixes a Start menu crash. Phone Link previews are gradually rolling out to Insiders with Phone Link version 1.26021.3.0 or later.
Changes 2 new · 5 improved · 6 fixes -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewBeta ChannelBuild 26220.9022
Taskbar position controls and smaller icons, plus SMB backup fix
Beta Channel Insiders get taskbar position and size controls, Search changes, and fixes for update rollbacks, network backups, and files incorrectly flagged as internet downloads.
Changes 3 new · 4 improved · 3 fixes -
Windows 11 · 26H1Windows 11 26H1 Windows 11 26H1 Optional previewPreviewKB5101681
Preview moves version 26H1 to build 28000.2608
Advances version 26H1 to OS build 28000.2608. Windows may request a restart.
Build 28000.2608Replaced by KB5121000 → -
Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Optional previewPreviewKB5101684
Builds advance for 24H2 and 25H2
Advances Windows 11, versions 25H2 and 24H2, to builds 26200.8973 and 26100.8973. Updates for 24H2 Home and Pro end October 13, 2026.
Builds 26100.8973 26200.8973Replaced by KB5121003 → -
Windows 11 · Future platformsWindows 11 Windows 11 Insider Future platforms Insider PreviewExperimental ChannelBuild 29634.1000
Voice isolation and braille display support
Adds Voice Isolation in Voice Access and support for HID braille displays in Narrator, alongside account, input, and reliability changes.
Changes 3 new · 10 improved -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28120.2546
HID braille support and configurable smart-card session disconnects
Adds Narrator support for HID braille displays, more Voice Access languages, and configurable smart-card disconnects for remote sessions. It also fixes a Settings crash.
Changes 4 new · 3 improved · 1 fix -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewBeta ChannelBuild 28020.2539
HID braille support and a Graphics settings crash fix
Adds HID braille display support and more Voice Access languages, and fixes a crash on the Graphics settings page.
Changes 4 new · 4 improved · 1 fix -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewRelease Preview ChannelBuild 28000.2605
Widgets, Bluetooth audio and Windows Update controls
Brings gradual changes to Widgets, Bluetooth, accessibility and other Windows features, plus fixes and improvements for Release Preview Insiders.
Changes 10 new · 57 improved · 9 fixes -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewExperimental ChannelBuild 26300.8935
Faster File Explorer and an Insider install fix
The Experimental Channel build speeds up File Explorer, adds touch scrolling to Recommended files, and fixes an error that could stop recent Insider builds from installing.
Changes 10 improved · 4 fixes -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewBeta ChannelBuild 26220.8925
Touchpad gesture controls and a more customizable Start menu
Adds touchpad gesture controls, updates Start and File Explorer, and improves braille display support. It also fixes an installation error affecting some recent Insider builds.
Changes 9 new · 8 improved · 1 fix -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewRelease Preview ChannelBuild 26200.8968
Voice Isolation and peripheral fingerprint sign-in
Adds Voice Isolation to Voice Access and extends Windows Hello Enhanced Sign-in Security to supported peripheral fingerprint readers, alongside other gradual changes.
Changes 8 new · 27 improved · 3 fixes -
Windows 11 · 24H2Windows 11 Windows 11 Insider 24H2 Insider PreviewRelease Preview ChannelBuild 26100.8968
Voice Isolation and peripheral fingerprint sign-in
The Release Preview build adds Voice Access speech options and support for external fingerprint readers, alongside File Explorer, touchpad, and reliability changes. It covers Windows 11 versions 24H2 and 25H2.
Changes 8 new · 27 improved · 3 fixes -
Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Out-of-band updateOut-of-bandKB5121767
Installation requires a restart
Updates Windows 11 versions 25H2 and 24H2. Installing it requires a restart.
Builds 26100.8894 26200.8894Replaced by KB5101684 → -
SQL Server · CU7SQL Server 2025 CU7 SQL Server 2025 CU7 Cumulative update
JSON corruption fixes; recovery monitoring can still crash
CU7 fixes 10 issues, including JSON corruption and a crash in recovery monitoring queries. A separate open issue can still cause an access violation when `sys.dm_exec_requests` runs during database recovery.
-
SQL Server · CU26SQL Server 2022 CU26 SQL Server 2022 CU26 Cumulative update
SQL injection fix, while recovery queries can still trigger crashes
Includes 12 fixes, including a SQL injection fix. A known issue can still cause an access violation when `sys.dm_exec_requests` runs during database recovery.
-
Windows 11 · 26H1Windows 11 26H1 Windows 11 26H1 Security updateZero-day UpdatedKB5101649
Exploited Shell spoofing flaw; picture-password sign-up ends
A Windows Shell spoofing flaw is already being exploited, and a BitLocker bypass flaw is public. New picture-password enrollment also ends.
-
Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Security updateZero-day UpdatedKB5101650
Exploited Windows Shell spoofing flaw patched; picture passwords retired
An actively exploited Windows Shell spoofing flaw is patched. New picture passwords can no longer be set up, and the update addresses problems with Office apps and Recycle Bin prompts.
-
Windows 11 · 23H2Windows 11 23H2 Windows 11 23H2 Security updateZero-day UpdatedKB5099414
Windows Shell spoofing flaw exploited; RDP adds SHA-2 support
An actively exploited Windows Shell spoofing flaw is addressed. Trusted Remote Desktop publishers can now use SHA-2 certificate thumbprints.
-
Windows 10 · 21H2, 22H2Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security updateZero-day UpdatedKB5099539
Shell spoofing flaw exploited; Secure Boot and RDP protections updated
A Windows Shell spoofing flaw is already being exploited, and the update adds Secure Boot status reporting and SHA-2 support for trusted RDP publishers. Some keyboard shortcuts might stop responding in rare cases.
-
Windows 10 · 1809Windows 10 1809 Windows 10 1809 Security update Also for Windows ServerZero-day UpdatedKB5099538
Exploited Shell and AD FS flaws patched; Secure Boot coverage expands
Patches exploited Windows Shell and Active Directory Federation Services flaws, and expands automatic Secure Boot certificate coverage. Some keyboard shortcuts might briefly stop working in rare cases.
-
Windows 10 · 1607Windows 10 1607 Windows 10 1607 Security update Also for Windows ServerZero-day UpdatedKB5099535
Exploited AD FS flaw patched; unregistered TDI apps may stop working
Attackers are exploiting an AD FS privilege flaw. This release also tightens TDI transport rules, which might stop apps using unregistered third-party transports.
-
Windows Server · 2025Windows Server 2025 Windows Server 2025 Security updateZero-day UpdatedKB5099536
Actively exploited AD FS and Shell flaws addressed
The update addresses actively exploited flaws in AD FS and Windows Shell, along with a publicly disclosed BitLocker flaw. It also adds cryptography support and fixes several reported problems.
Build 26100.33158Security 390 CVEs 31 critical 2 exploitedKnown issues 1 openReplaced by KB5120233 →