The Update Bureau
Monthly security update
- Version 26H1 28000.2704 KB5121000 → 26H1
- Version 24H2 / 25H2 26100.9168 KB5121003 → 24H2, 25H2
- Version 23H2 22631.7517 KB5120240 → 23H2
Release volume
45
updates released
16 fewer than July (61), vs 50/mo in 2026.
Security flaws fixed
276
vulnerabilities
-261 flaws compared to July (537).
Critical & urgent
24
critical · 1 zero-day
43 critical in July.
2026 Year-to-Date Trend
1,486 security flaws fixed across 398 updates in 2026
121 critical flaws and 13 exploited zero-days patched across the 8 published months of 2026.
Distinct security flaws fixed per month
Jan – Aug 2026
Monthly security update
- Version 21H2 / 22H2 19044.7663 KB5120249 → 21H2, 22H2
- Version 1809 17763.9121 KB5120238 → 1809
- Version 1607 14393.9418 KB5120418 → 1607
Monthly security update
- Version 2025 26100.33296 KB5120233 → 2025
- Version 2022 20348.5499 KB5120242 → 2022
- Version 2019 17763.9121 KB5120238 → 2019
- Version 2016 14393.9418 KB5120418 → 2016
Monthly security update
- .NET 3.5 / 4.8.1 · Windows 11 26H1 KB5120711 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 25H2, Windows Server 2025 KB5120708 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 24H2 KB5120710 → 3.5, 4.8.1
- .NET 3.5 / 4.8.1 · Windows 11 23H2 KB5120713 → 3.5, 4.8.1
+7 more
KB5120709 3.5, 4.8.1 · KB5120714 3.5, 4.8.1 · KB5120701 3.5, 4.8 · KB5120705 3.5, 4.8 · KB5120703 3.5, 4.8 · KB5120702 4.8 · KB5120698 3.5, 4.7.2
Monthly security update
- Subscription Edition (SE) 16.0.19725.20522 KB5002893 → SE
- Version 2019 16.0.10417.20198 KB5002894 → 2019
- Version 2016 16.0.5565.1001 KB5002905 → 2016
Monthly security update
- Version RTM 15.2.2562.46 KB5121573 → SE
- Version CU15 · ESU only 15.2.1748.49 KB5121574 → 2019
- Version CU14 · ESU only 15.2.1544.44 KB5121575 → 2019
- Version CU23 · ESU only 15.1.2507.72 KB5121576 → 2016
Monthly security update
- No Patch Tuesday security update this month —
Monthly security update
- Office Online Server 16.0.10417.20197 KB5002895 → OOS
Vulnerabilities fixed, by version
All updates
-
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28120.2824
Desktop wallpaper improvements and automatic Wi-Fi in recovery
Adds saved Wi-Fi support in Windows Recovery Environment and improves desktop backgrounds, File Explorer Home, Magnifier, and emoji.
Changes 4 new · 12 improved · 1 fix -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewBeta ChannelBuild 28020.2818
Saved Wi-Fi in recovery and fixes for desktop backgrounds
Adds saved Wi-Fi use in recovery, Emoji 17.0, and File Explorer section-state memory; it also fixes black desktop backgrounds after reboot.
Changes 3 new · 12 improved · 1 fix -
Windows 11 · 26H1Windows 11 26H1 Windows 11 26H1 Optional previewPreviewKB5120996
Voice isolation and external fingerprint sign-in arrive
Adds Voice Isolation and Korean support to Voice Access, plus support for external fingerprint readers with Windows Hello. It also improves File Explorer, power settings and other Windows features.
Build 28000.2804Replaced by KB5124012 → -
Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Optional previewPreviewKB5120998
Taskbar moves to four edges; WMIC utility removed
Adds extensive taskbar, Start menu, and Search customization. It also removes the WMIC utility from versions 24H2 and 25H2, while Secure Boot certificates for most devices have been expiring since June 2026.
Builds 26100.9278 26200.9278Replaced by KB5124008 → -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewRelease Preview ChannelBuild 26300.9278
Version 26H2 arrives through an enablement package
Windows 11 version 26H2 is being delivered to Release Preview Channel Insiders through an enablement package. The notes announce no feature changes.
-
.NET Framework · 3.5, 4.8.1PreviewKB5122386
Intermittent crashes in 64-bit .NET scenarios addressed
Addresses an issue that could cause intermittent crashes in some 64-bit .NET Framework scenarios. A restart is required after installation if affected files are in use.
Build 4.8.9345.0Replaced by KB5126053 → -
.NET Framework · 3.5, 4.8.1PreviewKB5122385
Intermittent crashes addressed in 64-bit .NET scenarios
Addresses intermittent crashes in some 64-bit .NET Framework scenarios.
Builds 4.8.9345.0 2.0.50727.9183Replaced by KB5126052 → -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28120.2760
Web-downloaded file previews and in-app purchases for elevated apps
Adds previews for PDFs and non-HTML files downloaded from the web, adds in-app purchase support for some apps, and fixes an invisible mouse cursor in certain apps.
Changes 2 new · 1 fix -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewExperimental ChannelBuild 26340.9233
Per-app privacy controls and a simpler AutoPlay dialog
Adds per-app desktop permissions, updates AutoPlay, and includes accessibility and file preview changes, plus fixes.
Changes 3 new · 4 improved · 3 fixes -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewBeta ChannelBuild 26220.9223
Weather-first lock screen widgets and apps that open maximized
Makes Weather the primary lock screen widget, adds an option to open apps maximized, and supports in-app purchases in packaged WinUI 3 apps that require elevation.
Changes 2 new · 1 improved -
Windows 11 · Future platformsWindows 11 Windows 11 Insider Future platforms Insider PreviewExperimental ChannelBuild 29648.1000
WMIC and Drag Tray removed; Magnifier launch fixed
Removes WMIC and Drag Tray, adjusts Windows Security, and fixes Magnifier launch and app UI shifting. Some Insiders still report a blinking cursor or error 0x80070005 when updating.
Changes 1 new · 1 improved · 2 fixes -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewExperimental ChannelBuild 28120.2738
WMIC and Drag Tray removed; Settings and Magnifier fixes
Removes WMIC and Drag Tray, fixes crashes in Settings and Magnifier, and includes a safeguard that might prevent PUBG: BATTLEGROUNDS from launching.
Changes 2 fixes -
Windows 11 · 26H1Windows 11 Windows 11 Insider 26H1 Insider PreviewBeta ChannelBuild 28020.2731
WMIC and Drag Tray removed; Settings and Magnifier fixes
Removes WMIC and Drag Tray, and fixes a Settings crash and an issue launching Magnifier.
Changes 2 fixes -
Windows 11 · 26H2Windows 11 Windows 11 Insider 26H2 Insider PreviewExperimental ChannelBuild 26340.9212
File Explorer gets a redesigned menu and recovery reuses Wi-Fi
Adds a redesigned File Explorer menu and saved-Wi-Fi networking in recovery. It also removes Drag Tray and includes input, Settings, and app fixes.
Changes 6 new · 12 improved · 4 fixes -
Windows 11 · 25H2Windows 11 Windows 11 Insider 25H2 Insider PreviewBeta ChannelBuild 26220.9202
Faster File Explorer Home and fixes for Settings and Arm64 apps
Build 26220.9202 for the Beta Channel speeds up File Explorer Home and improves touch browsing. It also includes fixes for Settings, file previews, and app crashes on Arm64 PCs.
Changes 6 improved · 3 fixes -
SQL Server · CU8SQL Server 2025 CU8 SQL Server 2025 CU8 Cumulative update
Database recovery queries can trigger access violations; JSON fixes included
Includes 11 fixes for SQL Server 2025. It also has an open issue where querying requests during database recovery might cause an access violation and dump file.
-
Windows 11 · 26H1Windows 11 26H1 Windows 11 26H1 Security updateZero-day UpdatedKB5121000
Exploited WinSock flaw patched; Drop Tray removed
An actively exploited flaw in the WinSock driver is patched, and Drop Tray and its Settings control are removed.
-
Windows 11 · 24H2, 25H2Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Security updateZero-day UpdatedKB5121003
Secure Boot targeting expands; Drop Tray is removed
Secure Boot updates reach more eligible PCs, while Drop Tray and its Multitasking setting are removed. The update also closes an actively exploited WinSock driver flaw.
Builds 26100.9168 26200.9168Security 195 CVEs 7 critical 1 exploitedKnown issues 1 with a workaroundReplaced by KB5120998 → -
Windows 11 · 23H2Windows 11 23H2 Windows 11 23H2 Security updateZero-day UpdatedKB5120240
WinSock driver flaw patched; File History backups improve
A flaw in the WinSock support driver listed as exploited is addressed, and File History backups to network shares become more reliable.
-
Windows 10 · 21H2, 22H2Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security updateZero-day UpdatedKB5120249
Exploited Winsock driver flaw patched; File History backups fixed
Attackers are exploiting a flaw in the Winsock Ancillary Function Driver that can let them gain higher access. Scheduled File History backups to network shares also work again.
-
Windows 10 · 1809Windows 10 1809 Windows 10 1809 Security update Also for Windows ServerZero-day UpdatedKB5120238
Exploited networking flaw; File History backups fixed
Attackers are exploiting a Windows networking flaw to gain higher privileges. File History backups to SMB network shares also work again.
-
Windows 10 · 1607Windows 10 1607 Windows 10 1607 Security update Also for Windows ServerZero-day UpdatedKB5120418
Exploited WinSock driver flaw patched; File History backups restored
An exploited WinSock driver flaw is patched, and failed File History network backups are fixed. Secure Boot certificate updates continue to reach eligible devices.
-
Windows Server · 2025Windows Server 2025 Windows Server 2025 Security updateZero-day UpdatedKB5120233
Winsock driver flaw under attack; DFS file previews improved
An actively exploited Winsock driver flaw gets a security fix. File Explorer also handles files on DFS drives better after network reconnects.
Build 26100.33296Security 216 CVEs 19 critical 1 exploitedKnown issues 1 openReplaced by KB5122871 → -
Windows Server · 2022Windows Server 2022 Windows Server 2022 Security updateZero-day UpdatedKB5120242
WinSock driver flaw under active attack
An actively exploited elevation-of-privilege flaw affects the Ancillary Function Driver for WinSock. The update also improves Secure Boot certificate targeting.
Build 20348.5499Security 195 CVEs 19 critical 1 exploitedKnown issues 1 openReplaced by KB5122882 → -
Windows Server · 2019Windows Server 2019 Windows Server 2019 Security update Also for Windows 10Zero-day UpdatedKB5120238
Exploited WinSock flaw patched; SMB backups recover
An actively exploited WinSock driver flaw is patched, and scheduled File History backups to network shares work again. Secure Boot certificate coverage also expands.