Microsoft Security Advisory CVE-2024-43485 | .NET Denial of Service Vulnerability
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Text.Json 6.0.x and 8.0.x. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
In System.Text.Json 6.0.x and 8.0.x, applications which deserialize input to a model with an [ExtensionData] property can be vulnerable to an algorithmic complexity attack resulting in Denial of Service.
Announcement
Announcement for this issue can be found at dotnet/announcements#329
Mitigation factors
JSON models which do not utilize the [ExtensionData] feature are not impacted by this vulnerability.
Affected software
- Any .NET 8.0 application running on .NET 8.0.8 or earlier.
- Any .NET 6.0 aplication running on .NET 6.0.33 or earlier.
- Any application consuming one of the vulnerable packages.
Affected Packages
The vulnerability affects any Microsoft .NET Core project if it uses any of affected packages versions listed below
.NET 8
| Package name |
Affected version |
Patched version |
| System.Text.Json |
>= 8.0.0, <= 8.0.4 |
8.0.5 |
.NET 6
| Package name |
Affected version |
Patched version |
| System.Text.Json |
>= 6.0.0, <= 6.0.9 |
6.0.10 |
Advisory FAQ
How do I know if I am affected?
If you have a runtime or SDK with a version listed, or an affected package listed in affected software or affected packages, you're exposed to the vulnerability.
How do I fix the issue?
- To fix the issue please install the latest version of .NET 8.0 or .NET 6.0. 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.
- .NET Framework-based applications and other application types need to perform a package update.
- If you have .NET 6.0 or greater installed, you can list the versions you have installed by running the
dotnet --info command. You will see output like the following;
.NET Core SDK (reflecting any global.json):
Version: 8.0.200
Commit: 8473146e7d
Runtime Environment:
OS Name: Windows
OS Version: 10.0.18363
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\6.0.300\
Host (useful for support):
Version: 8.0.3
Commit: 8473146e7d
.NET Core SDKs installed:
8.0.200 [C:\Program Files\dotnet\sdk]
.NET Core runtimes installed:
Microsoft.AspAspNetCore.App 8.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspAspNetCore.App]
Microsoft.AspNetCore.App 8.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.WindowsDesktop.App 8.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
To install additional .NET Core runtimes or SDKs:
https://aka.ms/dotnet-download
.NET 8.0 and .NET 6.0 updates are also available from Microsoft Update. To access this either type "Check for updates" in your Windows search, or open Settings, choose Update & Security and then click Check for Updates.
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 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 .NET 8.0 or .NET 6.0, please email details to secure@microsoft.com. Reports may qualify for the Microsoft .NET Core & .NET 5 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/runtime and https://github.com/dotnet/aspnet/. 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.
External Links
CVE-2024-43485
Revisions
V1.0 (October 08, 2024): Advisory published.
Version 1.0
Last Updated 2024-10-08
Microsoft Security Advisory CVE-2024-43485 | .NET Denial of Service Vulnerability
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Text.Json 6.0.x and 8.0.x. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
In System.Text.Json 6.0.x and 8.0.x, applications which deserialize input to a model with an
[ExtensionData]property can be vulnerable to an algorithmic complexity attack resulting in Denial of Service.Announcement
Announcement for this issue can be found at dotnet/announcements#329
Mitigation factors
JSON models which do not utilize the
[ExtensionData]feature are not impacted by this vulnerability.Affected software
Affected Packages
The vulnerability affects any Microsoft .NET Core project if it uses any of affected packages versions listed below
.NET 8
.NET 6
Advisory FAQ
How do I know if I am affected?
If you have a runtime or SDK with a version listed, or an affected package listed in affected software or affected packages, you're exposed to the vulnerability.
How do I fix the issue?
dotnet --infocommand. You will see output like the following;.NET 8.0 and .NET 6.0 updates are also available from Microsoft Update. To access this either type "Check for updates" in your Windows search, or open Settings, choose Update & Security and then click Check for Updates.
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 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 .NET 8.0 or .NET 6.0, please email details to secure@microsoft.com. Reports may qualify for the Microsoft .NET Core & .NET 5 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/runtime and https://github.com/dotnet/aspnet/. 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.
External Links
CVE-2024-43485
Revisions
V1.0 (October 08, 2024): Advisory published.
Version 1.0
Last Updated 2024-10-08