CVE-2026-69304 ASP.NET Core Denial of Service Vulnerability
Medium 5.9
Published
Updated
Check this codebase for CVE-2026-69304 and fix it if it is affected.
What it is: CVE-2026-69304 is a medium-severity denial of service vulnerability in Microsoft .Net, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-69304 in the wild and no public exploit code.
Affected packages and fixed versions:
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 10.0.0; fixed in 10.0.12
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 10.0.0; fixed in 10.0.12
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 11.0.0-preview.1; fixed in 11.0.0-rc.1
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 11.0.0-preview.1; fixed in 11.0.0-rc.1
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 8.0.0; fixed in 8.0.31
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 8.0.0; fixed in 8.0.31
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 9.0.0; fixed in 9.0.20
- Microsoft.AspNetCore.Server.IISIntegration (NuGet): affected from 9.0.0; fixed in 9.0.20
- aspnet-core (Bitnami): affected from 8.0.0; fixed in 8.0.28, 9.0.17, 10.0.9
- dotnet (Bitnami): affected from 8.0.0; fixed in 8.0.31, 9.0.20, 10.0.12
- dotnet-sdk (Bitnami): affected from 8.0.0; fixed in 8.0.31, 9.0.20, 10.0.12
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-69304/ (Markdown: https://insights.sbomify.com/CVE-2026-69304/index.md)
An unauthorized attacker can cause a denial of service in ASP.NET Core by exploiting improper handling of highly compressed data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-69304?
CVE-2026-69304 is a medium-severity denial of service vulnerability in Microsoft .Net, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper handling of highly compressed data (data amplification) in ASP.NET Core allows an unauthorized attacker to deny service over a network.
Weakness: CWE-409
Which versions are affected by CVE-2026-69304?
11 open source packages ship an affected version, including Microsoft.AspNetCore.Server.IISIntegration, aspnet-core and dotnet. It affects 4 products.
| Package | Affected | Fixed in |
|---|---|---|
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 10.0.0 | 10.0.12 |
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 10.0.0 | 10.0.12 |
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 11.0.0-preview.1 | 11.0.0-rc.1 |
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 11.0.0-preview.1 | 11.0.0-rc.1 |
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 8.0.0 | 8.0.31 |
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 8.0.0 | 8.0.31 |
5 more packages
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 9.0.0 | 9.0.20 |
Microsoft.AspNetCore.Server.IISIntegration NuGet | From 9.0.0 | 9.0.20 |
aspnet-core Bitnami | From 8.0.0 | 8.0.28, 9.0.17, 10.0.9 |
dotnet Bitnami | From 8.0.0 | 8.0.31, 9.0.20, 10.0.12 |
dotnet-sdk Bitnami | From 8.0.0 | 8.0.31, 9.0.20, 10.0.12 |
Linux distribution packages (28)
aspnetcore-runtime-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
aspnetcore-runtime-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
aspnetcore-runtime-dbg-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
aspnetcore-runtime-dbg-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
aspnetcore-targeting-pack-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
aspnetcore-targeting-pack-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
dotnet-apphost-pack-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
dotnet-apphost-pack-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
dotnet-hostfxr-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
dotnet-hostfxr-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
dotnet-runtime-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
dotnet-runtime-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
dotnet-runtime-dbg-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
dotnet-runtime-dbg-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
dotnet-sdk-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.130-0.2.hum1 |
dotnet-sdk-8.0-source-built-artifacts Red Hat:hummingbird:1 | All versions | 0:8.0.130-0.2.hum1 |
dotnet-sdk-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
dotnet-sdk-9.0-source-built-artifacts Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
dotnet-sdk-aot-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
dotnet-sdk-dbg-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.130-0.2.hum1 |
dotnet-sdk-dbg-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
dotnet-targeting-pack-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.30-0.2.hum1 |
dotnet-targeting-pack-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.18-2.1.hum1 |
dotnet-templates-8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.130-0.2.hum1 |
dotnet-templates-9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
dotnet8.0 Red Hat:hummingbird:1 | All versions | 0:8.0.130-0.2.hum1 |
dotnet9.0 Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
netstandard-targeting-pack-2.1 Red Hat:hummingbird:1 | All versions | 0:9.0.119-2.1.hum1 |
Products include Microsoft .Net, Microsoft Asp.net Core, Microsoft Visual Studio 2022, Microsoft Visual Studio 2026.
How do I fix CVE-2026-69304?
Upgrade Microsoft.AspNetCore.Server.IISIntegration to a fixed version for your release line: 10.0.12, 11.0.0-rc.1, 8.0.31 or 9.0.20.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-69304 being exploited?
There is no known exploitation of CVE-2026-69304 in the wild and no public exploit code.
Other vulnerabilities in Microsoft .Net
- CVE-2024-43498 .NET and Visual Studio Remote Code Execution Vulnerability
- CVE-2024-0057 NET, .NET Framework, and Visual Studio Security Feature Bypass Vulnerability
- CVE-2026-96957 .NET Security Feature Bypass Vulnerability
- CVE-2026-69439 .NET and Visual Studio Elevation of Privilege Vulnerability
- CVE-2026-71328 .NET and Visual Studio Remote Code Execution Vulnerability
Sources
Also known as BELL-CVE-2026-69304, BIT-aspnet-core-2026-69304, BIT-dotnet-2026-69304, BIT-dotnet-sdk-2026-69304, GHSA-8cp2-47hg-mfgh, MINI-3787-8vm6-3g39 and 4 more.