Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 6.0, .NET 7.0 and .NET 8.0 . This advisory also provides guidance on what developers can do to update their applications to address this vulnerability.
A security feature bypass vulnerability exists when Microsoft .NET Framework-based applications use X.509 chain building APIs but do not completely validate the X.509 certificate due to a logic flaw. An attacker could present an arbitrary untrusted certificate with malformed signatures, triggering a bug in the framework. The framework will correctly report that X.509 chain building failed, but it will return an incorrect reason code for the failure. Applications which utilize this reason code to make their own chain building trust decisions may inadvertently treat this scenario as a successful chain build. This could allow an adversary to subvert the app's typical authentication logic.
Within .NET, only the WindowsDesktop shared runtime contains inbox components which utilize X.509 chain building APIs in a vulnerable manner. Other project types, such as web applications, are not impacted by this vulnerability unless they explicitly invoke the X.509 chain building APIs themselves in a vulnerable manner or they consume an external package which does this on their behalf.
Affected software
NuGet & NuGet Packages
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 6.8.0 version or earlier.
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 6.7.0 version or earlier.
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 6.6.1 version or earlier.
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 6.4.2 version or earlier.
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 6.3.3 version or earlier.
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 6.0.5 version or earlier.
Any NuGet.exe, NuGet.CommandLine, NuGet.Packaging 5.11.5 version or earlier.
Any .NET SDK 6.0.126 or earlier, or 6.0.418 or earlier.
Any .NET SDK 7.0.115 or earlier, or 7.0.312 or earlier, or 7.0.405 or earlier.
Any .NET SDK 8.0.101 or earlier.
How do I know if I am affected?
If you have a NuGet package or .NET SDK with a version listed in affected software, you're exposed to the vulnerability.
How do I fix the issue?
To fix the issue, please install the latest version of .NET 6.0, .NET 7.0 or .NET 8.0 and NuGet (NuGet.exe, NuGet.CommandLine, NuGet. Packaging versions). 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.
You can get the version of NuGet.exe by running the nuget command. You should see an output like the following:
NuGet Version: 6.0.0.280
usage: NuGet <command> [args] [options]
Type 'NuGet help <command>' for help on a specific command.
To install additional .NET Core runtimes or SDKs:
https://www.nuget.org/downloads
You can list the versions you have installed by running the dotnet --info command. You should see an output like the following:
.NET Core SDK (reflecting any global.json):
Version: 6.0.300
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: 6.0.5
Commit: 8473146e7d
.NET Core SDKs installed:
6.0.300 [C:\Program Files\dotnet\sdk]
.NET Core runtimes installed:
Microsoft.AspNetCore.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
To install additional .NET Core runtimes or SDKs:
https://aka.ms/dotnet-download
If you're using .NET 7.0, you should download and install SDK 7.0.116 (for Visual Studio 2022 v17.4), or SDK 7.0.313 (for Visual Studio 2022 v17.6), or 7.0.406 (for Visual Studio 2022 v17.7) from https://dotnet.microsoft.com/download/dotnet-core/7.0.
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 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 7.0 or .NET 6.0, please email details to secure@microsoft.com. Reports may qualify for the Microsoft .NET Core & .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 repo is located at https://github.com/NuGet/NuGet.Client . The Announcements repo 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.
Microsoft Security Advisory CVE-2024-0057 | NuGet Client Security Feature bypass Vulnerability
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 6.0, .NET 7.0 and .NET 8.0 . This advisory also provides guidance on what developers can do to update their applications to address this vulnerability.
A security feature bypass vulnerability exists when Microsoft .NET Framework-based applications use X.509 chain building APIs but do not completely validate the X.509 certificate due to a logic flaw. An attacker could present an arbitrary untrusted certificate with malformed signatures, triggering a bug in the framework. The framework will correctly report that X.509 chain building failed, but it will return an incorrect reason code for the failure. Applications which utilize this reason code to make their own chain building trust decisions may inadvertently treat this scenario as a successful chain build. This could allow an adversary to subvert the app's typical authentication logic.
Discussion
Discussion for this issue can be found at https://github.com/NuGet/Home/issues/13241
Mitigation factors
Within .NET, only the WindowsDesktop shared runtime contains inbox components which utilize X.509 chain building APIs in a vulnerable manner. Other project types, such as web applications, are not impacted by this vulnerability unless they explicitly invoke the X.509 chain building APIs themselves in a vulnerable manner or they consume an external package which does this on their behalf.
Affected software
NuGet & NuGet Packages
GitHub Advisory
.NET SDK(s)
How do I know if I am affected?
If you have a NuGet package or .NET SDK with a version listed in affected software, you're exposed to the vulnerability.
How do I fix the issue?
To fix the issue, please install the latest version of .NET 6.0, .NET 7.0 or .NET 8.0 and NuGet (NuGet.exe, NuGet.CommandLine, NuGet. Packaging versions). 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.
You can get the version of NuGet.exe by running the
nugetcommand. You should see an output like the following:You can list the versions you have installed by running the
dotnet --infocommand. You should see an output like the following: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 7.0 or .NET 6.0, please email details to secure@microsoft.com. Reports may qualify for the Microsoft .NET Core & .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 repo is located at https://github.com/NuGet/NuGet.Client . The Announcements repo 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 2024-0057
Revisions
V1.0 (February 13, 2024): Advisory published.
Version 1.0
Last Updated 2024-02-13