CVE-2023-36799

Microsoft Security Advisory CVE-2023-36799: .NET Denial of Service Vulnerability

<a name="executive-summary"></a>Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 7.0 and .NET 6.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A vulnerability exists in .NET where reading a maliciously crafted X.509 certificate may result in Denial of Service. This issue only affects Linux systems.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/275

<a name="mitigation-factors"></a>Mitigation factors

Microsoft has not identified any mitigating factors for this vulnerability.

<a name="affected-software"></a>Affected software

• Any .NET 7.0 application running on .NET 7.0.10 or earlier.
• Any .NET 6.0 application running on .NET 6.0.21 or earlier.

If your application uses the following package versions, ensure you update to the latest version of .NET.

<a name=".NET 7"></a>.NET 7

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.NETCore.App.Runtime.linux-arm64 | >= 7.0.0, <= 7.0.10 | 7.0.11 Microsoft.NETCore.App.Runtime.linux-musl-arm64 | >= 7.0.0, <= 7.0.10 | 7.0.11 Microsoft.NETCore.App.Runtime.linux-arm | >= 7.0.0, <= 7.0.10 | 7.0.11 Microsoft.NETCore.App.Runtime.linux-musl-arm | >= 7.0.0, <= 7.0.10 | 7.0.11 Microsoft.NETCore.App.Runtime.linux-x64 | >= 7.0.0, <= 7.0.10 | 7.0.11 Microsoft.NETCore.App.Runtime.linux-musl-x64 | >= 7.0.0, <= 7.0.10 | 7.0.11

<a name=".NET 6"></a>.NET 6

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.NETCore.App.Runtime.linux-arm64 | >= 6.0.0, <= 6.0.21 | 6.0.22 Microsoft.NETCore.App.Runtime.linux-musl-arm64 | >= 6.0.0, <= 6.0.21 | 6.0.22 Microsoft.NETCore.App.Runtime.linux-arm | >= 6.0.0, <= 6.0.21 | 6.0.22 Microsoft.NETCore.App.Runtime.linux-musl-arm | >= 6.0.0, <= 6.0.21 | 6.0.22 Microsoft.NETCore.App.Runtime.linux-x64 | >= 6.0.0, <= 6.0.21 | 6.0.22 Microsoft.NETCore.App.Runtime.linux-musl-x64 | >= 6.0.0, <= 6.0.21 | 6.0.22

Advisory FAQ

<a name="how-affected"></a>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, you're exposed to the vulnerability.

<a name="how-fix"></a>How do I fix the issue?

• To fix the issue please install the latest version of .NET 6.0 or .NET 7.0. 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.
• If you are using one of the affected packages, please update to the patched version listed above.
• 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…

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.122 and .NET Runtime 6.0.22.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET Core and Visual Studio Denial of Service Vulnerability

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.122 and .NET Runtime 6.0.22.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.122 and .NET Runtime 6.0.22.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.111 and .NET Runtime 7.0.11.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.111 and .NET Runtime 7.0.11.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.124 and .NET Runtime 6.0.24.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.124 and .NET Runtime 6.0.24.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.113 and .NET Runtime 7.0.13.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 7.0.113 and .NET Runtime 7.0.13.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET Core and Visual Studio Denial of Service Vulnerability

.NET Core and Visual Studio Denial of Service Vulnerability

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.124 and .NET Runtime 6.0.24.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

.NET is a managed-software framework. It implements a subset of the .NET framework APIs and several new APIs, and it includes a CLR implementation.

New versions of .NET that address a security vulnerability are now available. The updated versions are .NET SDK 6.0.124 and .NET Runtime 6.0.24.

Security Fix(es):

• dotnet: Denial of Service with Client Certificates using .NET Kestrel (CVE-2023-36799)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Kevin Jones discovered that .NET did not properly process certain X.509 certificates. An attacker could possibly use this issue to cause a denial of service.

USN-6362-1 fixed vulnerabilities in .Net. It was discovered that the fix for CVE-2023-36799 was incomplete. This update fixes the problem.

Original advisory details:

Kevin Jones discovered that .NET did not properly process certain X.509 certificates. An attacker could possibly use this issue to cause a denial of service.