Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.
SignalR Redis scale-out can mishandle case-mismatched group removal and leave subscriptions in a state that permits persistent resource amplification and denial of service.
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/509
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:CThe tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 |
| Package | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 |
Compare the deployed ASP.NET Core runtime and the application's resolved Microsoft.AspNetCore.SignalR.StackExchangeRedis package version with the affected ranges above. Self-contained applications include their own runtime.
Update both the ASP.NET Core runtime and the Microsoft.AspNetCore.SignalR.StackExchangeRedis package to the applicable patched versions above. Restart affected framework-dependent applications after installing the runtime update. Rebuild and redeploy applications after updating the package; self-contained applications must also be rebuilt with the patched runtime. Updating a machine-wide runtime or SDK alone does not update an application's standalone package references.
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. Further information can be found in the MSRC Report an Issue FAQ.
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.
You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. 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.
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.
V1.0 (November 10, 2026): Advisory published.
{
"cwe_ids": [
"CWE-401"
],
"github_reviewed": true,
"github_reviewed_at": "2026-11-11T00:23:32Z",
"nvd_published_at": null,
"severity": "HIGH"
}