# KB5003203: May 2021 security update

KB5003203, released May 11, 2021, fixes 11 CVEs across 2 products. None of them is reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/fix/microsoft/kb5003203
- Platform: Microsoft
- Released: May 11, 2021
- Priority: Urgent (Closes CVE-2021-28476, rated Critical)
- CVEs: 11, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/5003203

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Windows Server 2012](https://patchblox.com/security/data/product/microsoft/windows-server-2012.md) |  |  |
| [Windows Server 2012 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/windows-server-2012-server-core-installation.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-28476](https://patchblox.com/security/data/cve/CVE-2021-28476.md) | Urgent | Role: Windows Hyper-V | 9.9 | 0.3923 |  |
| [CVE-2021-31194](https://patchblox.com/security/data/cve/CVE-2021-31194.md) | Urgent | Windows OLE | 8.8 | 0.0235 |  |
| [CVE-2021-31188](https://patchblox.com/security/data/cve/CVE-2021-31188.md) | Urgent | Microsoft Graphics Component | 7.8 | 0.0137 | More likely |
| [CVE-2021-31186](https://patchblox.com/security/data/cve/CVE-2021-31186.md) | High | Windows RDP Client | 7.4 | 0.0297 |  |
| [CVE-2021-28455](https://patchblox.com/security/data/cve/CVE-2021-28455.md) | High | Jet Red and Access Connectivity | 8.8 | 0.0212 |  |
| [CVE-2021-31193](https://patchblox.com/security/data/cve/CVE-2021-31193.md) | High | Windows SSDP Service | 7.8 | 0.0052 |  |
| [CVE-2020-26144](https://patchblox.com/security/data/cve/CVE-2020-26144.md) | Routine | Windows Wireless Networking | 6.5 | 0.0491 |  |
| [CVE-2020-24588](https://patchblox.com/security/data/cve/CVE-2020-24588.md) | Routine | Windows Wireless Networking | 6.5 | 0.0361 |  |
| [CVE-2020-24587](https://patchblox.com/security/data/cve/CVE-2020-24587.md) | Routine | Windows Wireless Networking | 6.5 | 0.0259 |  |
| [CVE-2021-31184](https://patchblox.com/security/data/cve/CVE-2021-31184.md) | Routine | Microsoft Windows IrDA | 5.5 | 0.0156 |  |
| [CVE-2021-28479](https://patchblox.com/security/data/cve/CVE-2021-28479.md) | Routine | Windows CSC Service | 5.5 | 0.0076 |  |

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Data as of 2026-11-07T12:40:37Z 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

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