# KB5001393: April 2021 security update KB5001393, released April 13, 2021, fixes 55 CVEs across 4 products. None of them is reported as exploited. Patch Radar priority: Urgent. - Web page: https://patchblox.com/security/fix/microsoft/kb5001393 - Platform: Microsoft - Released: Apr 13, 2021 - Priority: Urgent (Closes CVE-2021-28325, exploitation more likely) - CVEs: 55, exploited: 0, on CISA KEV: 0 - Vendor advisory: https://support.microsoft.com/help/5001393 ## Applies to | Product | Release | Fixed in | |---|---|---| | [Windows 8.1 for 32-bit systems](https://patchblox.com/security/data/product/microsoft/windows-8.1-for-32-bit-systems.md) | | | | [Windows 8.1 for x64-based systems](https://patchblox.com/security/data/product/microsoft/windows-8.1-for-x64-based-systems.md) | | | | [Windows Server 2012 R2](https://patchblox.com/security/data/product/microsoft/windows-server-2012-r2.md) | | | | [Windows Server 2012 R2 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2012-r2-server-core-installation.md) | | | ## CVEs this fix closes | CVE | Priority | Component | CVSS | EPSS | Exploitation | |---|---|---|---:|---:|---| | [CVE-2021-28325](https://patchblox.com/security/data/cve/CVE-2021-28325.md) | Urgent | Windows SMB Server | 6.5 | 0.6410 | More likely | | [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-2021-27072](https://patchblox.com/security/data/cve/CVE-2021-27072.md) | Urgent | Windows Win32K | 7.0 | 0.0065 | More likely | | [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-2021-27096](https://patchblox.com/security/data/cve/CVE-2021-27096.md) | High | Windows NTFS | 7.8 | 0.0059 | | | [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-2021-28447](https://patchblox.com/security/data/cve/CVE-2021-28447.md) | Routine | Windows Early Launch Antimalware Driver | 4.4 | 0.0218 | | | [CVE-2021-28444](https://patchblox.com/security/data/cve/CVE-2021-28444.md) | Routine | Role: Windows Hyper-V | 5.7 | 0.0187 | | | [CVE-2021-28316](https://patchblox.com/security/data/cve/CVE-2021-28316.md) | Routine | Windows WLAN Auto Config Service | 4.2 | 0.0116 | | | [CVE-2021-27094](https://patchblox.com/security/data/cve/CVE-2021-27094.md) | Routine | Windows ELAM | 4.4 | 0.0104 | | | [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-2021-28435](https://patchblox.com/security/data/cve/CVE-2021-28435.md) | Routine | Windows Event Tracing | 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 | | --- Data as of 2026-11-08T13:06:02Z UTC. 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