# KB5037040: April 2024 security update

KB5037040, released April 9, 2024, fixes 1 CVE across 4 products. None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/microsoft/kb5037040
- Platform: Microsoft
- Released: Apr 9, 2024
- Priority: High (Closes CVE-2024-21409, high severity)
- CVEs: 1, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/5037040

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.6.2-4.7-4.7.1-4.7.2-on-windows-server-2012-r2.md) |  |  |
| [Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2012 R2 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.6.2-4.7-4.7.1-4.7.2-on-windows-server-2012-r2-server-core-installation.md) |  |  |
| [Microsoft .NET Framework 4.8 on Windows Server 2012 R2](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.8-on-windows-server-2012-r2.md) |  |  |
| [Microsoft .NET Framework 4.8 on Windows Server 2012 R2 (Server Core installation)](https://patchblox.com/security/data/product/microsoft/microsoft-.net-framework-4.8-on-windows-server-2012-r2-server-core-installation.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2024-21409](https://patchblox.com/security/data/cve/CVE-2024-21409.md) | High | .NET and Visual Studio | 7.3 | 0.0251 |  |

---

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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.