# KB5001389: April 2021 security update

KB5001389, released April 13, 2021, fixes 47 CVEs across 4 products. None of them is reported as exploited. Patch Radar priority: Urgent. The product is no longer supported.

- Web page: https://patchblox.com/security/fix/microsoft/kb5001389
- Platform: Microsoft
- Released: Apr 13, 2021
- Priority: Urgent (Closes CVE-2021-27095, rated Critical)
- CVEs: 47, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/5001389

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows Server 2008 for 32-bit Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/windows-server-2008-for-32-bit-systems-service-pack-2.md) |  |  |
| [Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2008-for-32-bit-systems-service-pack-2-server-core-installation.md) |  |  |
| [Windows Server 2008 for x64-based Systems Service Pack 2](https://patchblox.com/security/data/product/microsoft/windows-server-2008-for-x64-based-systems-service-pack-2.md) |  |  |
| [Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2008-for-x64-based-systems-service-pack-2-server-core-installation.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-27095](https://patchblox.com/security/data/cve/CVE-2021-27095.md) | Urgent | Windows Media Player | 7.8 | 0.0435 |  |
| [CVE-2021-28333](https://patchblox.com/security/data/cve/CVE-2021-28333.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0254 |  |
| [CVE-2021-28329](https://patchblox.com/security/data/cve/CVE-2021-28329.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28330](https://patchblox.com/security/data/cve/CVE-2021-28330.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28331](https://patchblox.com/security/data/cve/CVE-2021-28331.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28332](https://patchblox.com/security/data/cve/CVE-2021-28332.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28334](https://patchblox.com/security/data/cve/CVE-2021-28334.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28335](https://patchblox.com/security/data/cve/CVE-2021-28335.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28336](https://patchblox.com/security/data/cve/CVE-2021-28336.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28337](https://patchblox.com/security/data/cve/CVE-2021-28337.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28338](https://patchblox.com/security/data/cve/CVE-2021-28338.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28339](https://patchblox.com/security/data/cve/CVE-2021-28339.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28343](https://patchblox.com/security/data/cve/CVE-2021-28343.md) | Urgent | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28315](https://patchblox.com/security/data/cve/CVE-2021-28315.md) | Urgent | Windows Media Player | 7.8 | 0.0160 |  |
| [CVE-2021-28439](https://patchblox.com/security/data/cve/CVE-2021-28439.md) | High | Windows TCP/IP | 7.5 | 0.0653 |  |
| [CVE-2021-26415](https://patchblox.com/security/data/cve/CVE-2021-26415.md) | High | Windows Installer | 7.8 | 0.0357 |  |
| [CVE-2021-28445](https://patchblox.com/security/data/cve/CVE-2021-28445.md) | High | Windows Network File System | 8.1 | 0.0290 |  |
| [CVE-2021-28327](https://patchblox.com/security/data/cve/CVE-2021-28327.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0254 |  |
| [CVE-2021-28340](https://patchblox.com/security/data/cve/CVE-2021-28340.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0254 |  |
| [CVE-2021-28344](https://patchblox.com/security/data/cve/CVE-2021-28344.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0254 |  |
| [CVE-2021-28356](https://patchblox.com/security/data/cve/CVE-2021-28356.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0254 |  |
| [CVE-2021-28341](https://patchblox.com/security/data/cve/CVE-2021-28341.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28342](https://patchblox.com/security/data/cve/CVE-2021-28342.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28345](https://patchblox.com/security/data/cve/CVE-2021-28345.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28346](https://patchblox.com/security/data/cve/CVE-2021-28346.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28352](https://patchblox.com/security/data/cve/CVE-2021-28352.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28353](https://patchblox.com/security/data/cve/CVE-2021-28353.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28354](https://patchblox.com/security/data/cve/CVE-2021-28354.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28355](https://patchblox.com/security/data/cve/CVE-2021-28355.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28357](https://patchblox.com/security/data/cve/CVE-2021-28357.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28358](https://patchblox.com/security/data/cve/CVE-2021-28358.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-28434](https://patchblox.com/security/data/cve/CVE-2021-28434.md) | High | Windows Remote Procedure Call Runtime | 8.8 | 0.0247 |  |
| [CVE-2021-27089](https://patchblox.com/security/data/cve/CVE-2021-27089.md) | High | Microsoft Internet Messaging API | 7.8 | 0.0242 |  |
| [CVE-2021-28446](https://patchblox.com/security/data/cve/CVE-2021-28446.md) | High | Windows Portmapping | 7.1 | 0.0081 |  |
| [CVE-2021-28350](https://patchblox.com/security/data/cve/CVE-2021-28350.md) | High | Microsoft Graphics Component | 7.8 | 0.0079 |  |
| [CVE-2021-28348](https://patchblox.com/security/data/cve/CVE-2021-28348.md) | High | Microsoft Graphics Component | 7.8 | 0.0071 |  |
| [CVE-2021-28349](https://patchblox.com/security/data/cve/CVE-2021-28349.md) | High | Microsoft Graphics Component | 7.8 | 0.0071 |  |
| [CVE-2021-28440](https://patchblox.com/security/data/cve/CVE-2021-28440.md) | High | Windows Installer | 7.0 | 0.0062 |  |
| [CVE-2021-28323](https://patchblox.com/security/data/cve/CVE-2021-28323.md) | Routine | Microsoft Windows DNS | 6.5 | 0.0461 |  |
| [CVE-2021-28328](https://patchblox.com/security/data/cve/CVE-2021-28328.md) | Routine | Microsoft Windows DNS | 6.5 | 0.0266 |  |
| [CVE-2021-27093](https://patchblox.com/security/data/cve/CVE-2021-27093.md) | Routine | Windows Kernel | 5.5 | 0.0086 |  |
| [CVE-2021-28309](https://patchblox.com/security/data/cve/CVE-2021-28309.md) | Routine | Windows Kernel | 5.5 | 0.0086 |  |
| [CVE-2021-28317](https://patchblox.com/security/data/cve/CVE-2021-28317.md) | Routine | Microsoft Windows Codecs Library | 5.5 | 0.0082 |  |
| [CVE-2021-28318](https://patchblox.com/security/data/cve/CVE-2021-28318.md) | Routine | Microsoft Graphics Component | 5.5 | 0.0081 |  |
| [CVE-2021-28437](https://patchblox.com/security/data/cve/CVE-2021-28437.md) | Routine | Windows Installer | 5.5 | 0.0081 | Disclosed |
| [CVE-2021-26413](https://patchblox.com/security/data/cve/CVE-2021-26413.md) | Routine | Windows Installer | 6.2 | 0.0076 |  |
| [CVE-2021-28443](https://patchblox.com/security/data/cve/CVE-2021-28443.md) | Routine | Windows Console Driver | 5.5 | 0.0069 |  |

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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
