Microsoft KB articles
Official Windows update notes, documented: improvements, known issues, and how to get each update, with the KB number, OS build and release date at a glance.
197 articles
KB5087539 - Windows Server 2025 Security Update (OS Build 26100.32860)
May 12, 2026 cumulative security update for Windows Server 2025, bringing OS build 26100.32860 with Secure Boot, connectivity, and AD CS improvements.
KB5089548: Windows 11 Version 26H1 May 2026 Security Update (OS Build 28000.2113)
KB5089548 is the May 12, 2026 Patch Tuesday cumulative security update for Windows 11 version 26H1, bringing devices to OS Build 28000.2113.
KB5089466: Windows 11 May 2026 Hotpatch (OS Builds 26200.8390 and 26100.8390)
May 12, 2026 hotpatch security update for Windows 11 Enterprise LTSC 2024, versions 25H2 and 24H2, delivering OS builds 26200.8390 and 26100.8390.
KB5089549: Windows 11 May 2026 Cumulative Update (OS Builds 26200.8457 and 26100.8457)
May 12, 2026 cumulative security update for Windows 11 versions 25H2 and 24H2, delivering OS builds 26200.8457 and 26100.8457 with security fixes and quality improvements.
KB5087537: Windows Server 2016 / Windows 10 LTSB 2016 May 2026 Update (OS Build 14393.9140)
May 12, 2026 cumulative security update for Windows Server 2016 and Windows 10 LTSB 2016, delivering OS build 14393.9140 with security fixes and quality improvements.
KB5083806 - Windows 11 Version 26H1 Preview Update (OS Build 28000.1896)
Optional non-security preview update for Windows 11 version 26H1, released April 30, 2026, delivering OS build 28000.1896 with AI, display, and reliability improvements.
KB5083631: Windows 11 OS Builds 26200.8328 and 26100.8328 Preview - April 30, 2026
Optional non-security preview update for Windows 11 versions 25H2 and 24H2, releasing OS builds 26200.8328 and 26100.8328 on April 30, 2026.
KB5091572 (OS Build 14393.9062): April 19, 2026 Out-of-Band Update for Windows Server 2016
Out-of-band fix for Windows Server 2016 (OS Build 14393.9062) addressing a domain controller LSASS crash introduced by the April 14, 2026 security update.
KB5091573 (OS Build 17763.8647) Out-of-Band Update for Windows Server 2019 - April 19, 2026
Out-of-band update for Windows Server 2019 (OS Build 17763.8647) released April 19, 2026, fixing a domain controller LSASS crash in multi-domain PAM environments.
KB5091575 - Windows Server 2022 Out-of-Band Update (OS Build 20348.5024)
Out-of-band cumulative update for Windows Server 2022 released April 19, 2026, fixing a critical LSASS/domain controller startup issue introduced by KB5082142.
KB5091157: Windows Server 2025 April 19 2026 Out-of-Band Update (OS Build 26100.32698)
Non-security out-of-band cumulative update for Windows Server 2025 fixing a domain controller LSASS crash affecting PAM in multi-domain forests. Released April 19, 2026.
KB5082420: Cumulative Update for .NET Framework 3.5 and 4.8.1 - Windows 11 24H2 (April 2026)
April 14, 2026 security and reliability update for .NET Framework 3.5 and 4.8.1 on Windows 11 version 24H2. Addresses six CVEs and one WCF bug.
KB5082417: .NET Framework 3.5 and 4.8.1 Cumulative Update for Windows 11 25H2 and Server 24H2 (April 2026)
April 14, 2026 security and reliability update for .NET Framework 3.5 and 4.8.1 on Windows 11 version 25H2 and Microsoft server operating system 24H2.
KB5082052: Windows 11 23H2 Cumulative Update (OS Build 22631.6936) - April 2026
April 14, 2026 security cumulative update for Windows 11 version 23H2, bringing OS build 22631.6936 with security fixes, Secure Boot improvements, and Remote Desktop phishing protections.
KB5083768: Windows 11 version 26H1 Security Update (OS Build 28000.1836) - April 14, 2026
April 2026 cumulative security update for Windows 11 version 26H1, bringing OS build 28000.1836 with Secure Boot, networking, and Remote Desktop improvements.
KB5082200: April 14, 2026 Security Update for Windows 10 (OS Builds 19045.7184 and 19044.7184)
April 14, 2026 cumulative security update for Windows 10 22H2, LTSC 2021, and IoT Enterprise LTSC 2021, delivering OS builds 19045.7184 and 19044.7184.
KB5082063 - Windows Server 2025 Cumulative Update (OS Build 26100.32690) April 2026
April 14, 2026 security cumulative update for Windows Server 2025, delivering OS build 26100.32690 with security fixes, Kerberos, Bluetooth, RDP, and networking improvements.
KB5082198 (OS Build 14393.9060) - April 2026 Security Update for Windows Server 2016 and Windows 10 LTSB 2016
April 14, 2026 security update for Windows Server 2016 and Windows 10 LTSB 2016, bringing OS build 14393.9060 with security fixes and quality improvements.
April 14, 2026 - KB5082123 (OS Build 17763.8644) Security Update
April 2026 cumulative security update for Windows Server 2019 and Windows 10 Enterprise LTSC 2019, delivering OS build 17763.8644 with security fixes and quality improvements.
KB5082142: Windows Server 2022 Cumulative Update - April 14, 2026 (OS Build 20348.5020)
April 14, 2026 security cumulative update for Windows Server 2022, bringing OS build 20348.5020 with security fixes, quality improvements, and non-security changes.