# KB5075912: February 2026 cumulative update for Windows 10 21H2

KB5075912, released February 10, 2026, fixes 24 CVEs across 6 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/kb5075912
- 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/5075912

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows 10 Version 21H2 for 32-bit Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-21h2-for-32-bit-systems.md) |  |  |
| [Windows 10 Version 21H2 for ARM64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-21h2-for-arm64-based-systems.md) |  |  |
| [Windows 10 Version 21H2 for x64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-21h2-for-x64-based-systems.md) |  |  |
| [Windows 10 Version 22H2 for 32-bit Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-22h2-for-32-bit-systems.md) |  |  |
| [Windows 10 Version 22H2 for ARM64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-22h2-for-arm64-based-systems.md) |  |  |
| [Windows 10 Version 22H2 for x64-based Systems](https://patchblox.com/security/data/product/microsoft/windows-10-version-22h2-for-x64-based-systems.md) |  |  |

## 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-2026-21244](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-2026-21255](https://patchblox.com/security/data/cve/CVE-2026-21255.md) | High | Role: Windows Hyper-V | 8.8 | 0.0038 |  |
| [CVE-2026-21242](https://patchblox.com/security/data/cve/CVE-2026-21242.md) | High | Windows Subsystem for Linux | 7.0 | 0.0036 |  |
| [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-2026-21237](https://patchblox.com/security/data/cve/CVE-2026-21237.md) | High | Windows Subsystem for Linux | 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 |  |

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Data as of 2026-11-07T06:34:28Z 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
