CVE-2026-96222

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in verschiedenen Versionen von Microsoft Windows Server und Microsoft Windows ausnutzen, um seine Privilegien auf administrative Rechte zu erhöhen, um beliebigen Code auszuführen, um Informationen offenzulegen, um einen Denial of Service herbeizuführen, um den Benutzer zu täuschen und andere, nicht näher spezifizierte Auswirkungen zu verursachen.

Ein Angreifer kann mehrere Schwachstellen in Microsoft .NET Framework, Microsoft .NET, Microsoft ASP.NET, Microsoft Visual Studio 2022, Microsoft Visual Studio 2026, Microsoft Visual Studio Code, Microsoft SysInternals und Microsoft PowerShell ausnutzen, um seine Privilegien zu erhöhen, um Code auszuführen, um Informationen offenzulegen, um Sicherheitsmechanismen zu umgehen und um einen Denial of Service Zustand herbeizuführen.

To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in System.Security.Cryptography.Xml. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. `KeyInfoX509Data` can accept serialized certificate formats containing attacker-controlled chain metadata instead of requiring a plain X.509 certificate, contributing to certificate-forgery and token-spoofing paths. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/474 ## CVSS Details - **Version:** 3.1 - **Severity:** High - **Score:** 7.4 - **Vector:** `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N` - **Weakness:** CWE-295 (Improper Certificate Validation) ## Affected Platforms - **Platforms:** Windows, Linux, macOS - **Architectures:** All ## <a name="affected-packages"></a>Affected Packages The vulnerability affects Microsoft .NET projects that use an affected package version listed below. Package name | Affected version | Patched version ------------ | ---------------- | --------------- [System.Security.Cryptography.Xml](https://www.nuget.org/packages/System.Security.Cryptography.Xml) | >= 8.0.0, <= 8.0.4 | 8.0.5 ## 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. 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. 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/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. ### 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-2026-96222](https://www.cve.org/CVERecord?id=CVE-2026-96222) ### Acknowledgements - Vaisha Bernard with Eye Security ### Revisions V1.0 (10/13/2026): Advisory published.

Improper certificate validation in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.

Improper certificate validation in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.