# CVE-2026-69304: ASP.NET Core Denial of Service Vulnerability

CVE-2026-69304 is fixed in 12 products on 2 platforms, first by Microsoft ASP.NET Core Hosting Bundle 9.0 9.0.20, released August 14, 2026. 3 other affected products have no fix yet. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-69304
- Priority: Routine
- CVSS: 5.9 (Important)
- EPSS: 0.0086
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Vendor exploitability assessment: Exploitation Less Likely
- Published: Sep 8, 2026
- Weakness: Improper Handling of Highly Compressed Data (Data Amplification)
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69304

## Description

<p>Improper handling of highly compressed data (data amplification) in ASP.NET Core allows an unauthorized attacker to deny service over a network.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | .NET 10.0 runtime installed on Windows |  | [KB5126106](https://patchblox.com/security/data/fix/microsoft/kb5126106.md) | Sep 8, 2026 |
| Microsoft | .NET 8.0 runtime installed on Windows |  | [KB5126104](https://patchblox.com/security/data/fix/microsoft/kb5126104.md) | Sep 8, 2026 |
| Microsoft | .NET 9.0 runtime installed on Windows |  | [KB5126105](https://patchblox.com/security/data/fix/microsoft/kb5126105.md) | Sep 8, 2026 |
| Microsoft | ASP.NET Core 10.0 |  | [KB5126106](https://patchblox.com/security/data/fix/microsoft/kb5126106.md) | Sep 8, 2026 |
| Microsoft | ASP.NET Core 8.0 |  | [KB5126104](https://patchblox.com/security/data/fix/microsoft/kb5126104.md) | Sep 8, 2026 |
| Microsoft | ASP.NET Core 9.0 |  | [KB5126105](https://patchblox.com/security/data/fix/microsoft/kb5126105.md) | Sep 8, 2026 |
| Windows apps | Microsoft .NET Windows Desktop Runtime 10.0 | 10.0.12 | [Microsoft .NET Windows Desktop Runtime 10.0 10.0.12](https://patchblox.com/security/data/fix/windows-app/microsoft.dotnet.desktopruntime.10-10.0.12.md) | Aug 22, 2026 |
| Windows apps | Microsoft .NET Windows Desktop Runtime 8.0 | 8.0.31 | [Microsoft .NET Windows Desktop Runtime 8.0 8.0.31](https://patchblox.com/security/data/fix/windows-app/microsoft.dotnet.desktopruntime.8-8.0.31.md) | Aug 22, 2026 |
| Windows apps | Microsoft .NET Windows Desktop Runtime 9.0 | 9.0.20 | [Microsoft .NET Windows Desktop Runtime 9.0 9.0.20](https://patchblox.com/security/data/fix/windows-app/microsoft.dotnet.desktopruntime.9-9.0.20.md) | Aug 21, 2026 |
| Windows apps | Microsoft ASP.NET Core Hosting Bundle 10.0 | 10.0.12 | [Microsoft ASP.NET Core Hosting Bundle 10.0 10.0.12](https://patchblox.com/security/data/fix/windows-app/microsoft.dotnet.hostingbundle.10-10.0.12.md) | Aug 22, 2026 |
| Windows apps | Microsoft ASP.NET Core Hosting Bundle 8.0 | 8.0.31 | [Microsoft ASP.NET Core Hosting Bundle 8.0 8.0.31](https://patchblox.com/security/data/fix/windows-app/microsoft.dotnet.hostingbundle.8-8.0.31.md) | Aug 22, 2026 |
| Windows apps | Microsoft ASP.NET Core Hosting Bundle 9.0 | 9.0.20 | [Microsoft ASP.NET Core Hosting Bundle 9.0 9.0.20](https://patchblox.com/security/data/fix/windows-app/microsoft.dotnet.hostingbundle.9-9.0.20.md) | Aug 14, 2026 |

## No fix yet

| Platform | Product | Status |
|---|---|---|
| Windows apps | Microsoft Windows Desktop Runtime - 8.0.25 (arm64) | no-fix |
| Windows apps | Microsoft Windows Desktop Runtime - 8.0.25 (x64) | no-fix |
| Windows apps | Microsoft Windows Desktop Runtime - 8.0.25 (x86) | no-fix |

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Data as of 2026-11-08T06:59:42Z 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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