The latest KB for each servicing branch, from Microsoft's public release-information tables. Dates are availability dates, not evidence of what your devices installed.
| Servicing branch | Latest release | Last security (B) release | CVEs fixed by B | Known issues | Status |
|---|---|---|---|---|---|
| Windows 11 | |||||
| Windows 11, version 26H1 | KB5124006 D build 28000.3086 · 22 Sep 2026 | KB5124012 8 Sep 2026 | 62753 critical1 exploited | 3 open | Active |
| Windows 11, version 25H2 | KB5124010 D build 26200.9550 · 22 Sep 2026 | KB5124008 8 Sep 2026 | 62753 critical1 exploited | 3 open | Active |
| Windows 11, version 24H2 | KB5124010 D build 26100.9550 · 22 Sep 2026 | KB5124008 8 Sep 2026 | 62853 critical1 exploited | 3 open | Active |
| Windows 11, version 23H2Enterprise and Education | KB5129242 OOB build 22631.7584 · 14 Sep 2026 | KB5122880 8 Sep 2026 | 60252 critical1 exploited | 1 open | Active |
| Windows 11, version 22H2 | KB5066793 B build 22621.6060 · 14 Oct 2025 | Same as latest | — | — | Dormant · 11 mo |
| Windows 11, version 21H2 | KB5044280 B build 22000.3260 · 8 Oct 2024 | Same as latest | — | — | Dormant · 23 mo |
| Windows 10 | |||||
| Windows 10, version 22H2Extended Security Updates (ESU) | KB5129236 OOB build 19045.7727 · 14 Sep 2026 | KB5122878 8 Sep 2026 | 56848 critical1 exploited | 1 open | Active |
| Windows 10, version 21H2Enterprise LTSC 2021 and IoT Enterprise LTSC 2021 | KB5129236 OOB build 19044.7727 · 14 Sep 2026 | KB5122878 8 Sep 2026 | 56848 critical1 exploited | 1 open | Active |
| Windows 10, version 1809Enterprise LTSC 2019 | KB5129238 OOB build 17763.9247 · 14 Sep 2026 | KB5122876 8 Sep 2026 | 61254 critical1 exploited | 1 open | Active |
| Windows 10, version 1607Enterprise LTSB 2016 | KB5129239 OOB build 14393.9514 · 14 Sep 2026 | KB5123099 8 Sep 2026 | 54944 critical1 exploited | 1 open | Active |
| Windows 10, version 21H1 | KB5021233 B build 19043.2364 · 13 Dec 2022 | Same as latest | — | — | Dormant · 46 mo |
| Windows 10, version 20H2 | KB5026361 B build 19042.2965 · 9 May 2023 | Same as latest | — | — | Dormant · 41 mo |
| Windows 10, version 2004 | KB5008212 B build 19041.1415 · 14 Dec 2021 | Same as latest | — | — | Dormant · 58 mo |
| Windows 10, version 1909 | KB5013945 B build 18363.2274 · 10 May 2022 | Same as latest | — | — | Dormant · 53 mo |
| Windows 10, version 1903 | KB4592449 B build 18362.1256 · 8 Dec 2020 | Same as latest | — | — | Dormant · 70 mo |
| Windows 10, version 1803 | KB5003174 B build 17134.2208 · 11 May 2021 | Same as latest | — | — | Dormant · 65 mo |
| Windows 10, version 1709 | KB4580328 B build 16299.2166 · 13 Oct 2020 | Same as latest | — | — | Dormant · 72 mo |
| Windows 10, version 1703 | KB4520010 B build 15063.2108 · 8 Oct 2019 | Same as latest | — | — | Dormant · 84 mo |
| Windows 10, version 1511 | KB4093109 B build 10586.1540 · 10 Apr 2018 | Same as latest | — | — | Dormant · 103 mo |
| Windows 10, version 1507 (RTM)Enterprise LTSB 2015 | KB5065430 B build 10240.21128 · 9 Sep 2025 | Same as latest | — | — | Dormant · 12 mo |
| Windows Server | |||||
| Windows Server 2025 | KB5129235 OOB build 26100.33451 · 14 Sep 2026 | KB5122871 8 Sep 2026 | 67963 critical1 exploited | 1 open | Active |
| Windows Server 2022 | KB5129237 OOB build 20348.5631 · 14 Sep 2026 | KB5122882 8 Sep 2026 | 64160 critical1 exploited | 1 open | Active |
| Windows Server 2019 | KB5129238 OOB build 17763.9247 · 14 Sep 2026 | KB5122876 8 Sep 2026 | 61658 critical1 exploited | 1 open | Active |
| Windows Server 2016 | KB5129239 OOB build 14393.9514 · 14 Sep 2026 | KB5123099 8 Sep 2026 | 55348 critical1 exploited | 1 open | Active |