# KB5075904: February 2026 cumulative update for Windows 10 1809

KB5075904, released February 10, 2026, fixes 24 CVEs across 4 products. 5 of them are being exploited (CVE-2026-21510); 5 on CISA KEV. Patch Radar priority: Patch now.

- Web page: https://patchblox.com/security/fix/microsoft/kb5075904
- Platform: Microsoft
- Released: Feb 10, 2026
- Priority: Patch now (Closes CVE-2026-21510, exploited (CISA KEV))
- CVEs: 24, exploited: 5, on CISA KEV: 5
- Vendor advisory: https://support.microsoft.com/help/5075904

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows 10 Version 1809 for 32-bit Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-1809-for-32-bit-systems.md) |  | 17763.8389 |
| [Windows 10 Version 1809 for x64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-1809-for-x64-based-systems.md) |  | 17763.8389 |
| [Windows Server 2019](https://patchblox.com/security/data/product/microsoft/windows-server-2019.md) |  | 17763.8389 |
| [Windows Server 2019 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2019-server-core-installation.md) |  | 17763.8389 |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-21510](https://patchblox.com/security/data/cve/CVE-2026-21510.md) | Patch now | Windows Shell | 8.8 | 0.6124 | CISA KEV, Disclosed |
| [CVE-2026-21513](https://patchblox.com/security/data/cve/CVE-2026-21513.md) | Patch now | MSHTML Framework | 8.8 | 0.1585 | CISA KEV, Disclosed |
| [CVE-2026-21525](https://patchblox.com/security/data/cve/CVE-2026-21525.md) | Patch now | Windows Remote Access Connection Manager | 6.2 | 0.0504 | CISA KEV |
| [CVE-2026-21533](https://patchblox.com/security/data/cve/CVE-2026-21533.md) | Patch now | Windows Remote Desktop | 7.8 | 0.0434 | CISA KEV |
| [CVE-2026-21519](https://patchblox.com/security/data/cve/CVE-2026-21519.md) | Patch now | Desktop Window Manager | 7.8 | 0.0257 | CISA KEV |
| [CVE-2026-21238](https://patchblox.com/security/data/cve/CVE-2026-21238.md) | Urgent | Windows Ancillary Function Driver for WinSock | 7.8 | 0.0333 | More likely |
| [CVE-2026-21231](https://patchblox.com/security/data/cve/CVE-2026-21231.md) | Urgent | Windows Kernel | 7.8 | 0.0252 | More likely |
| [CVE-2026-21253](https://patchblox.com/security/data/cve/CVE-2026-21253.md) | Urgent | Mailslot File System | 7.0 | 0.0079 | More likely |
| [CVE-2026-20846](https://patchblox.com/security/data/cve/CVE-2026-20846.md) | High | Windows GDI+ | 7.5 | 0.0141 |  |
| [CVE-2026-21243](https://patchblox.com/security/data/cve/CVE-2026-21243.md) | High | Windows LDAP - Lightweight Directory Access Protocol | 7.5 | 0.0141 |  |
| [CVE-2026-21244](https://patchblox.com/security/data/cve/CVE-2026-21244.md) | High | Role: Windows Hyper-V | 7.3 | 0.0131 |  |
| [CVE-2026-21248](https://patchblox.com/security/data/cve/CVE-2026-21248.md) | High | Role: Windows Hyper-V | 7.3 | 0.0131 |  |
| [CVE-2026-21235](https://patchblox.com/security/data/cve/CVE-2026-21235.md) | High | Microsoft Graphics Component | 7.3 | 0.0073 |  |
| [CVE-2026-21247](https://patchblox.com/security/data/cve/CVE-2026-21247.md) | High | Role: Windows Hyper-V | 7.3 | 0.0058 |  |
| [CVE-2026-21508](https://patchblox.com/security/data/cve/CVE-2026-21508.md) | High | Windows Storage | 7.0 | 0.0044 |  |
| [CVE-2026-21236](https://patchblox.com/security/data/cve/CVE-2026-21236.md) | High | Windows Ancillary Function Driver for WinSock | 7.8 | 0.0044 |  |
| [CVE-2026-21239](https://patchblox.com/security/data/cve/CVE-2026-21239.md) | High | Windows Kernel | 7.8 | 0.0044 |  |
| [CVE-2026-21246](https://patchblox.com/security/data/cve/CVE-2026-21246.md) | High | Microsoft Graphics Component | 7.8 | 0.0044 |  |
| [CVE-2026-21251](https://patchblox.com/security/data/cve/CVE-2026-21251.md) | High | Windows Cluster Client Failover | 7.8 | 0.0044 |  |
| [CVE-2026-21255](https://patchblox.com/security/data/cve/CVE-2026-21255.md) | High | Role: Windows Hyper-V | 8.8 | 0.0038 |  |
| [CVE-2026-21240](https://patchblox.com/security/data/cve/CVE-2026-21240.md) | High | Windows HTTP.sys | 7.8 | 0.0028 |  |
| [CVE-2026-21234](https://patchblox.com/security/data/cve/CVE-2026-21234.md) | High | Windows Connected Devices Platform Service | 7.0 | 0.0027 |  |
| [CVE-2026-21249](https://patchblox.com/security/data/cve/CVE-2026-21249.md) | Routine | Windows NTLM | 3.3 | 0.1128 |  |
| [CVE-2026-21222](https://patchblox.com/security/data/cve/CVE-2026-21222.md) | Routine | Windows Kernel | 5.5 | 0.0060 |  |

---

Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.