Red Hat Security Advisory: .NET 9.0 security update

Fixed packages 23

Vulnerabilities 26

• Critical 9.4
  CVE-2026-88092

  ASP.NET Core Tampering Vulnerability

  Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an unauthorized attacker to perform tampering over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• Critical 9.1
  CVE-2026-70188

  ASP.NET Core Security Feature Bypass Vulnerability

  Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an unauthorized attacker to bypass a security feature over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 8.8
  CVE-2026-96230 Public exploit

  ASP.NET Core Remote Code Execution Vulnerability

  Improper neutralization of input during web page generation ('cross-site scripting') in ASP.NET Core allows an unauthorized attacker to execute code over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 Microsoft.AspNetCore.Components.WebAssembly.Server Ubuntu Alpine NuGet
  Oct 13, 2026
• High 8.1
  CVE-2026-70175

  ASP.NET Core Elevation of Privilege Vulnerability

  Improper authentication in ASP.NET Core allows an unauthorized attacker to elevate privileges over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 .NET 11.0 installed on Windows Linux Windows macOS Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.8
  CVE-2026-96225

  .NET Elevation of Privilege Vulnerability

  Improper link resolution before file access ('link following') in .NET allows an authorized attacker to elevate privileges locally.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 10.0 runtime Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.8
  CVE-2026-96231

  .NET Elevation of Privilege Vulnerability

  Improper link resolution before file access ('link following') in .NET allows an authorized attacker to elevate privileges locally.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 8.0 runtime Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-58280

  .NET Denial of Service Vulnerability

  Uncontrolled recursion in .NET allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.7.2 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-69651

  .NET Denial of Service Vulnerability

  Inefficient algorithmic complexity in .NET allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.7.2 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-70159

  ASP.NET Core Denial of Service Vulnerability

  Allocation of resources without limits or throttling in ASP.NET Core allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 Microsoft.AspNetCore.SignalR.Core Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-70179

  ASP.NET Core Elevation of Privilege Vulnerability

  Authentication bypass by spoofing in ASP.NET Core allows an authorized attacker to elevate privileges over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 Microsoft.AspNetCore.Authentication.Negotiate Ubuntu Alpine NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-70181

  ASP.NET Core Denial of Service Vulnerability

  Allocation of resources without limits or throttling in ASP.NET Core allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-70183

  ASP.NET Core Elevation of Privilege Vulnerability

  Concurrent execution using shared resource with improper synchronization ('race condition') in ASP.NET Core allows an authorized attacker to elevate privileges over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-70186

  ASP.NET Core Denial of Service Vulnerability

  Deadlock in ASP.NET Core allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-84008

  .NET Denial of Service Vulnerability

  Inefficient algorithmic complexity in .NET allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.8 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-96233

  ASP.NET Core Denial of Service Vulnerability

  Out-of-bounds write in ASP.NET Core allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.8 Microsoft .NET Framework 3.5 AND 4.7.2 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-96236

  ASP.NET Core Denial of Service Vulnerability

  Allocation of resources without limits or throttling in ASP.NET Core allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-96237

  .NET Remote Code Execution Vulnerability

  Inclusion of functionality from untrusted control sphere in .NET allows an unauthorized attacker to execute code over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 10.0 runtime Ubuntu Alpine
  Oct 13, 2026
• High 7.5
  CVE-2026-96958

  .NET Denial of Service Vulnerability

  Inefficient algorithmic complexity in .NET allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.7.2 Microsoft .NET Framework 3.5 AND 4.8 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-96959

  .NET Denial of Service Vulnerability

  Allocation of resources without limits or throttling in .NET allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.7.2 Microsoft .NET Framework 3.5 AND 4.8 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.5
  CVE-2026-96960

  .NET Denial of Service Vulnerability

  Asymmetric resource consumption (amplification) in .NET allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Microsoft .NET Framework 3.5 AND 4.7.2 Microsoft .NET Framework 3.5 AND 4.8 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• High 7.0
  CVE-2026-69806

  .NET Elevation of Privilege Vulnerability

  Exposure of sensitive information to an unauthorized actor in .NET allows an authorized attacker to elevate privileges locally.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 10.0 runtime Ubuntu Alpine
  Sep 8, 2026
• Medium 6.5
  CVE-2026-58649

  .NET Information Disclosure Vulnerability

  Origin validation error in .NET allows an unauthorized attacker to disclose information over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 8.0 runtime Ubuntu Alpine
  Sep 8, 2026
• Medium 6.5
  CVE-2026-96238

  .NET Security Feature Bypass Vulnerability

  Origin validation error in .NET allows an unauthorized attacker to bypass a security feature over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 10.0 runtime Ubuntu Alpine
  Oct 13, 2026
• Medium 5.9
  CVE-2026-66822

  .NET Information Disclosure Vulnerability

  Insertion of sensitive information into sent data in .NET allows an unauthorized attacker to disclose information over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 .NET 9.0 runtime .NET 10.0 runtime Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• Medium 5.9
  CVE-2026-70196

  ASP.NET Core Denial of Service Vulnerability

  Inefficient algorithmic complexity in ASP.NET Core allows an unauthorized attacker to deny service over a network.

  Microsoft Microsoft Visual Studio 2022 version 17.14 Microsoft Visual Studio 2026 version 18.10 ASP.NET Core 8.0 Ubuntu Alpine Wolfi NuGet
  Oct 13, 2026
• Medium 5.3
  CVE-2026-92707

  MessagePack: Nested arrays can blow past buffer length limits

  MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] …

  MessagePack-CSharp MessagePack-CSharp dotnet7 dotnet8-runtime Ubuntu Azure Linux Alpine NuGet
  Oct 15, 2026

References

• article
  https://access.redhat.com/security/updates/classification/#critical
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2528870
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2528921
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548778
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548781
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548784
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548786
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548787
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548790
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548791
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548792
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548793
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548796
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548798
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548799
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548800
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548803
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548804
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548805
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548806
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548807
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548808
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2548809
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_88424.json
• report
  https://access.redhat.com/security/cve/CVE-2026-58280
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-58280
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-58280
• report
  https://access.redhat.com/security/cve/CVE-2026-58649
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-58649
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-58649
• report
  https://access.redhat.com/security/cve/CVE-2026-66822
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-66822
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-66822
• report
  https://access.redhat.com/security/cve/CVE-2026-69651
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-69651
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-69651
• report
  https://access.redhat.com/security/cve/CVE-2026-69806
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-69806
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-69806