ASP.NET Core Denial of Service Vulnerability

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

Uncontrolled resource consumption in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Source published

9 Jun 2026 17:05:29 UTC

Source modified

10 Nov 2026 23:24:22 UTC

Saved here

11 Nov 2026 02:25:43 UTC

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CVE Program Terms of Use

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Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Uncontrolled resource consumption in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Source published

Jun 9, 2026, 5:05:29 PM (timezone not stated)

Source modified

Nov 10, 2026, 11:24:22 PM (timezone not stated)

Saved here

15 Nov 2026 14:02:51 UTC

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ENISA EUVD · source terms and attribution apply

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Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Uncontrolled resource consumption in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Source published

9 Jun 2026 17:17:26 UTC

Source modified

11 Nov 2026 00:19:00 UTC

Saved here

12 Nov 2026 17:18:54 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core SignalR and Blazor Server. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. A denial of service vulnerability exists in the MessagePack hub protocol used by SignalR and Blazor Server where an attacker can send deeply-nested MessagePack arrays to cause a stack overflow, resulting in a denial of service. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/405 ## Affected Platforms - **Platforms:** All - **Architectures:** All ## <a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below ### <a name=".NET 10"></a>.NET 10 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-x64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-arm64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-x64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x64) | >= 10.0.0, <= 10.0.8 | 10.0.9 [Microsoft.AspNetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x86) | >= 10.0.0, <= 10.0.8 | 10.0.9 ### <a name=".NET 10 SignalR"></a>Microsoft.AspNetCore.SignalR.Protocols.MessagePack (.NET 10) Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.AspNetCore.SignalR.Protocols.MessagePack](https://www.nuget.org/packages/Microsoft.AspNetCore.SignalR.Protocols.MessagePack) | >= 10.0.0, <= 10.0.8 | 10.0.9 ### <a name=".NET 9"></a>.NET 9 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-x64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-arm64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-x64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x64) | >= 9.0.0, <= 9.0.16 | 9.0.17 [Microsoft.AspNetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x86) | >= 9.0.0, <= 9.0.16 | 9.0.17 ### <a name=".NET 9 SignalR"></a>Microsoft.AspNetCore.SignalR.Protocols.MessagePack (.NET 9) Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.AspNetCore.SignalR.Protocols.MessagePack](https://www.nuget.org/packages/Microsoft.AspNetCore.SignalR.Protocols.MessagePack) | >= 9.0.0, <= 9.0.16 | 9.0.17 ### <a name=".NET 8"></a>.NET 8 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-x64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-arm64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-x64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x64) | >= 8.0.0, <= 8.0.27 | 8.0.28 [Microsoft.AspNetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x86) | >= 8.0.0, <= 8.0.27 | 8.0.28 ### <a name=".NET 8 SignalR"></a>Microsoft.AspNetCore.SignalR.Protocols.MessagePack (.NET 8) Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- [Microsoft.AspNetCore.SignalR.Protocols.MessagePack](https://www.nuget.org/packages/Microsoft.AspNetCore.SignalR.Protocols.MessagePack) | >= 8.0.0, <= 8.0.27 | 8.0.28 ## Advisory FAQ ### <a name="how-affected"></a>How do I know if I am affected? If using a package listed in [affected packages](#affected-packages), you're exposed to the vulnerability. ### <a name="how-fix"></a>How do I fix the issue? 1. To fix the issue please install the latest version of .NET 10.0, .NET 9.0, or .NET 8.0. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs. 2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the `dotnet --info` command. * If you're using .NET 8.0, you should download and install .NET 8.0.28 Runtime or .NET 8.0.xxx SDK from https://dotnet.microsoft.com/download/dotnet-core/8.0. * If you're using .NET 9.0, you should download and install .NET 9.0.17 Runtime or .NET 9.0.xxx SDK from https://dotnet.microsoft.com/download/dotnet-core/9.0. * If you're using .NET 10.0, you should download and install .NET 10.0.9 Runtime or .NET 10.0.xxx SDK from https://dotnet.microsoft.com/download/dotnet-core/10.0. Once you have installed the updated runtime or SDK, restart your apps for the update to take effect. Additionally, if you've deployed [self-contained applications](https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd) targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed. ## Other Information ### Reporting Security Issues If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the [MSRC Researcher Portal](https://msrc.microsoft.com/report/vulnerability/new). Further information can be found in the MSRC [Report an Issue FAQ](https://www.microsoft.com/msrc/faqs-report-an-issue). Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty. ### Support You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/aspnetcore. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue. ### Disclaimer The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. ### Acknowledgements Anonymous

Source published

15 Jun 2026 20:11:56 UTC

Source modified

10 Sep 2026 03:50:53 UTC

Saved here

23 Oct 2026 16:01:25 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH