The Update Bureau
Monthly security update
- Version 26H1 28000.1836 KB5083768 → 26H1
- Version 24H2 / 25H2 26100.8246 KB5083769 → 24H2, 25H2
- Version 23H2 22631.6936 KB5082052 → 23H2
Release volume
60
updates released
11 more than March (49), vs 47/mo in 2026.
Security flaws fixed
151
vulnerabilities
+94 flaws compared to March (57).
Critical & urgent
5
critical · 1 zero-day
1 critical in March, plus 6 out-of-band releases this month .
2026 Year-to-Date Trend
356 security flaws fixed across 187 updates in 2026
12 critical flaws and 7 exploited zero-days patched across the 4 published months of 2026.
Distinct security flaws fixed per month
Jan – Apr 2026
Monthly security update
- Version 21H2 / 22H2 19044.7184 KB5082200 → 21H2, 22H2
- Version 1809 17763.8644 KB5082123 → 1809
- Version 1607 14393.9060 KB5082198 → 1607
Monthly security update
- Version 2025 26100.32690 KB5082063 → 2025
- Version 2022 20348.5020 KB5082142 → 2022
- Version 2019 17763.8644 KB5082123 → 2019
- Version 2016 14393.9060 KB5082198 → 2016
Monthly security update
- .NET 3.5 / 4.8.1 · Windows 11 26H1 KB5082421 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 25H2, Windows Server 2025 KB5082417 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 24H2 KB5082420 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 23H2 KB5082424 → 3.5, 4.8.1
+7 more
KB5082419 3.5, 4.8.1 · KB5082425 3.5, 4.8.1 · KB5082426 3.5, 4.8 · KB5082427 3.5, 4.8 · KB5082414 3.5, 4.8 · KB5082411 4.8 · KB5082413 3.5, 4.7.2
Monthly security update
- Version CU3 + GDR 17.0.4030.1 KB5083245 → 2025
- Version GDR 17.0.1110.1 KB5084814 → 2025
- Version CU24 + GDR 16.0.4250.1 KB5083252 → 2022
- Version GDR 16.0.1175.1 KB5084815 → 2022
+6 more
KB5084816 2019 · KB5084817 2019 · KB5084818 2017 · KB5084819 2017 · KB5084820 2016 · KB5084821 2016
Monthly security update
- Subscription Edition (SE) 16.0.19725.20210 KB5002853 → SE
- Version 2019 16.0.10417.20114 KB5002854 → 2019
- Version 2016 16.0.5548.1003 KB5002861 → 2016
Monthly security update
- Office Online Server 16.0.10417.20113 KB5002855 → OOS
Vulnerabilities fixed, by version
All updates
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Windows 11 · 26H1Windows 11 26H1 Windows 11 26H1 Optional previewPreviewKB5083806
Narrator adds Copilot image descriptions; Remote Desktop warning fixed
Adds Copilot-powered image descriptions in Narrator and fixes a Remote Desktop security warning that could render incorrectly across monitors with different scaling.
Build 28000.1896Replaced by KB5089548 → -
Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Optional previewPreviewKB5083631
Xbox mode brings a full-screen gaming view to PCs
A full-screen Xbox mode and new input features arrive alongside File Explorer changes and fixes for Remote Desktop and notification hangs. This optional preview also has a BitLocker recovery-key issue on some managed devices.
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Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28020.1873
Voice typing moves animations onto the dictation key
Brings Xbox mode and voice typing changes, storage improvements, faster startup apps, and a Data Usage fix to Insiders in the Canary 28000 series Channel, including those not yet moved to Experimental (26H1).
Changes 6 improved · 1 fix -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewExperimental ChannelBuild 26300.8289
More Windows Update controls and better taskbar-edge Start detection
Dev Channel Insiders transitioning to Experimental get new Windows Update controls, changes to Start menu detection, and several fixes and improvements.
Changes 4 new · 4 improved · 1 fix -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewBeta ChannelBuild 26220.8283
Start menu edge clicks and Times New Roman diacritic support
Beta Channel Insiders get improved Start menu activation from the taskbar edge and better Times New Roman support for Greek and Cyrillic diacritical marks, alongside printer-driver and Group Policy Editor changes.
Changes 3 improved · 1 fix -
Windows 11 · Future platformsWindows 11 Windows 11 Insider Future platforms Insider PreviewExperimental ChannelBuild 29576.1000
Sound controls move into Settings and Task Manager adds NPU columns
Brings more audio controls into Settings, adds Task Manager columns for NPU and app isolation, and introduces point-in-time restore. Changes are rolling out gradually.
Changes 4 new · 4 improved · 1 fix -
Windows 10 · 1809Windows 10 1809 Windows 10 1809 Out-of-band update Also for Windows ServerOut-of-bandKB5091573
Secure Boot certificates face expiration; Azure checks updated
Includes updated Azure-hosted device certificate checks. Microsoft also warns that Secure Boot certificates have started expiring and recommends preparing in advance.
Build 17763.8647Replaced by KB5087538 → -
Windows 10 · 1607Windows 10 1607 Windows 10 1607 Out-of-band update Also for Windows ServerOut-of-bandKB5091572
Remote Desktop security warnings display correctly again
The update adds a resolution for incorrectly displayed Remote Desktop security warnings. It is available only from the Update Catalog and requires the latest servicing stack update.
Build 14393.9062Replaced by KB5087537 → -
Windows Server · 2025Windows Server 2025 Windows Server 2025 Out-of-band updateOut-of-bandKB5091157
Domain controller startup and update installation problems fixed
Domain controllers in some multi-domain forests can start again, and affected Server 2025 devices can install the April security update. The out-of-band release also includes open BitLocker, WSUS, and Remote Desktop issues.
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Windows Server · 2022Windows Server 2022 Windows Server 2022 Out-of-band updateOut-of-bandKB5091575
PAM-related domain controller startup failures fixed
Domain controllers in multi-domain forests using PAM can start again after restart failures caused by the April 14 update. This out-of-band release is available only from the Microsoft Update Catalog.
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Windows Server · 2019Windows Server 2019 Windows Server 2019 Out-of-band update Also for Windows 10Out-of-bandKB5091573
Fixes startup failures on multi-domain PAM domain controllers
Fixes startup problems on multi-domain domain controllers that use Privileged Access Management after installing the April 14 update. It is available only from the Microsoft Update Catalog.
Build 17763.8647Replaced by KB5087538 → -
Windows Server · 2016Windows Server 2016 Windows Server 2016 Out-of-band update Also for Windows 10Out-of-bandKB5091572
PAM domain controllers recover from startup failures
Fixes startup problems on Windows Server 2016 domain controllers with multi-domain forests using PAM after the April 14 update. It is available only from the Update Catalog.
Build 14393.9062Replaced by KB5087537 → -
Windows 11 · Future platformsWindows 11 Windows 11 Insider Future platforms Insider PreviewExperimental ChannelBuild 29570.1000
Xbox mode on PCs and adjustable touchpad right-click zones
Build 29570.1000 for Windows Insiders adds Xbox mode, more lock screen widgets, and touchpad right-click zone sizing, alongside policy and pen settings changes.
Changes 4 new · 3 improved -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28020.1863
False no-internet reports block some app sign-ins
Fixes a false no-internet report that prevented some apps from signing in.
Changes 1 fix -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewExperimental ChannelBuild 26300.8276
Clearer location settings and faster clipboard history
Build 26300.8276 for Dev Channel Insiders gradually improves location settings, File Explorer, Windows Hello fingerprint sign-in, clipboard history, and fonts.
Package KB5083726Changes 8 improved -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewBeta ChannelBuild 26220.8271
Clearer location controls and more consistent File Explorer search
Beta Channel Insiders get clearer location settings and gradual improvements to File Explorer, fingerprint sign-in, clipboard history, and font rendering.
Package KB5083728Changes 8 improved -
SQL Server · CU4SQL Server 2025 CU4 SQL Server 2025 CU4 Cumulative update
Fixes lost msdb permissions and Full-Text Search failures
CU4 includes 11 fixes for SQL Server 2025, including lost permissions during upgrades and failures in Full-Text Search. It also has two open known issues involving parallel SESSION_CONTEXT queries and MSDASQL linked servers.
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Windows 11 · 26H1Windows 11 26H1 Windows 11 26H1 Security update
Fixes 119 vulnerabilities (3 critical)
Remote code execution flaws in Remote Desktop, IKE and TCP/IP are among the security fixes. Secure Boot certificates and Remote Desktop warnings also get changes.
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Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Security update
Critical IKE and TCP/IP flaws; Secure Boot status added
Critical remote-code flaws affect Windows IKE and TCP/IP. The update also adds Secure Boot certificate status in Windows Security and hardens the blocklist for vulnerable drivers.
Builds 26100.8246 26200.8246Security 120 CVEs 2 criticalKnown issues 2 openReplaced by KB5083631 → -
Windows 11 · 23H2Windows 11 23H2 Windows 11 23H2 Security update
Remote Desktop shows connection settings; Microsoft sign-in fixed
Remote Desktop shows requested settings before connecting, and a Microsoft account sign-in error is fixed. The update also adds protections against vulnerable kernel drivers.
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Windows 10 · 21H2, 22H2Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
Critical IKE and TCP/IP remote-code flaws patched
The update fixes 106 security flaws, including two critical remote-code execution vulnerabilities in IKE and TCP/IP. It also fixes Microsoft-account sign-in problems and adds safer handling of Remote Desktop files.
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Windows 10 · 1809Windows 10 1809 Windows 10 1809 Security update Also for Windows Server
Critical IKE and TCP/IP flaws patched; .rdp files get safer prompts
Fixes 99 vulnerabilities, including two critical remote code execution flaws in IKE service extensions and TCP/IP. It also adds security checks when opening .rdp files and changes Secure Boot reporting.
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Windows 10 · 1607Windows 10 1607 Windows 10 1607 Security update Also for Windows Server
Critical IKE and TCP/IP remote-code flaws patched
Fixes 79 vulnerabilities, including two critical remote-code execution flaws in Windows IKE Service Extensions and TCP/IP. It also expands the phased rollout of new Secure Boot certificates.
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Windows Server · 2025Windows Server 2025 Windows Server 2025 Security update
Secure Boot hardening and new recovery-key and Remote Desktop issues
Secure Boot certificate updates reach more eligible devices, while changes to driver blocking and Windows Deployment Services can affect backup apps and Hands-Free Deployment. Some BitLocker, WSUS, and Remote Desktop issues remain listed.
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Windows Server · 2022Windows Server 2022 Windows Server 2022 Security update
Critical IKE flaw patched; BitLocker recovery risk remains
A critical flaw in the Windows IKE service could allow remote code execution. Some managed servers might also ask for a BitLocker recovery key after the first restart.