RHSA-2026:55856: Important: .NET 9.0 security, bug fix, and enhancement update

Published Aug 17, 2026
·
Updated

.NET is a fast, lightweight and modular platform for creating cross platform applications that work on Linux, macOS and Windows. It particularly focuses on creating console applications, web applications and micro-services. .NET contains a runtime conforming to .NET Standards a set of framework libraries, an SDK containing compilers and a 'dotnet' application to drive everything.SDK version: 9.0.120Runtime version: 9.0.19Security Fix(es): .NET: .NET Core: .NET Security Feature Bypass Vulnerability (CVE-2026-62899) .NET: .NET Information Disclosure Vulnerability (CVE-2026-62900) .NET: .NET Denial of Service Vulnerability (CVE-2026-62901) .NET: .NET Elevation of Privilege Vulnerability (CVE-2026-62909) Bug Fix(es) and Enhancement(s): Update .NET 9.0 to SDK 9.0.120 and Runtime 9.0.19 [rhel-9.8.z] (JIRA:RHEL-235476) 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.

Affected Software

81 affected componentsFixes available
redhat/dotnet9.0<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/aspnetcore-runtime<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/aspnetcore-runtime-dbg<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/aspnetcore-targeting-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-apphost-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-apphost-pack<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-hostfxr<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-hostfxr<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-runtime<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-runtime<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-runtime-dbg<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-sdk<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-sdk<9.0-debuginfo-9.0.120-1.el9_8
9.0-debuginfo-9.0.120-1.el9_8
redhat/dotnet-sdk-aot<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-sdk-aot<9.0-debuginfo-9.0.120-1.el9_8
9.0-debuginfo-9.0.120-1.el9_8
redhat/dotnet-sdk-dbg<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-targeting-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-templates<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet9.0-debuginfo<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/dotnet9.0-debugsource<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/netstandard-targeting-pack<2.1-9.0.120-1.el9_8
2.1-9.0.120-1.el9_8
redhat/aspnetcore-runtime<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/aspnetcore-runtime-dbg<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/aspnetcore-targeting-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-apphost-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-apphost-pack<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-hostfxr<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-hostfxr<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-runtime<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-runtime<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-runtime-dbg<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-sdk<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-sdk<9.0-debuginfo-9.0.120-1.el9_8
9.0-debuginfo-9.0.120-1.el9_8
redhat/dotnet-sdk-dbg<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-targeting-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-templates<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet9.0-debuginfo<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/dotnet9.0-debugsource<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/netstandard-targeting-pack<2.1-9.0.120-1.el9_8
2.1-9.0.120-1.el9_8
redhat/aspnetcore-runtime<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/aspnetcore-runtime-dbg<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/aspnetcore-targeting-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-apphost-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-apphost-pack<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-hostfxr<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-hostfxr<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-runtime<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-runtime<9.0-debuginfo-9.0.19-1.el9_8
9.0-debuginfo-9.0.19-1.el9_8
redhat/dotnet-runtime-dbg<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-sdk<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-sdk<9.0-debuginfo-9.0.120-1.el9_8
9.0-debuginfo-9.0.120-1.el9_8
redhat/dotnet-sdk-dbg<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet-targeting-pack<9.0-9.0.19-1.el9_8
9.0-9.0.19-1.el9_8
redhat/dotnet-templates<9.0-9.0.120-1.el9_8
9.0-9.0.120-1.el9_8
redhat/dotnet9.0-debuginfo<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/dotnet9.0-debugsource<9.0.120-1.el9_8
9.0.120-1.el9_8
redhat/netstandard-targeting-pack<2.1-9.0.120-1.el9_8
2.1-9.0.120-1.el9_8
redhat/aspnetcore-runtime<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/aspnetcore-runtime-dbg<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/aspnetcore-targeting-pack<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/dotnet-apphost-pack<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/dotnet-apphost-pack<9.0-debuginfo-9.0.19-1.el9_8.aa
9.0-debuginfo-9.0.19-1.el9_8.aa
redhat/dotnet-hostfxr<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/dotnet-hostfxr<9.0-debuginfo-9.0.19-1.el9_8.aa
9.0-debuginfo-9.0.19-1.el9_8.aa
redhat/dotnet-runtime<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/dotnet-runtime<9.0-debuginfo-9.0.19-1.el9_8.aa
9.0-debuginfo-9.0.19-1.el9_8.aa
redhat/dotnet-runtime-dbg<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/dotnet-sdk<9.0-9.0.120-1.el9_8.aa
9.0-9.0.120-1.el9_8.aa
redhat/dotnet-sdk<9.0-debuginfo-9.0.120-1.el9_8.aa
9.0-debuginfo-9.0.120-1.el9_8.aa
redhat/dotnet-sdk-aot<9.0-9.0.120-1.el9_8.aa
9.0-9.0.120-1.el9_8.aa
redhat/dotnet-sdk-aot<9.0-debuginfo-9.0.120-1.el9_8.aa
9.0-debuginfo-9.0.120-1.el9_8.aa
redhat/dotnet-sdk-dbg<9.0-9.0.120-1.el9_8.aa
9.0-9.0.120-1.el9_8.aa
redhat/dotnet-targeting-pack<9.0-9.0.19-1.el9_8.aa
9.0-9.0.19-1.el9_8.aa
redhat/dotnet-templates<9.0-9.0.120-1.el9_8.aa
9.0-9.0.120-1.el9_8.aa
redhat/dotnet9.0-debuginfo<9.0.120-1.el9_8.aa
9.0.120-1.el9_8.aa
redhat/dotnet9.0-debugsource<9.0.120-1.el9_8.aa
9.0.120-1.el9_8.aa
redhat/netstandard-targeting-pack<2.1-9.0.120-1.el9_8.aa
2.1-9.0.120-1.el9_8.aa
redhat/dotnet-sdk<9.0-source-built-artifacts-9.0.120-1.el9_8
9.0-source-built-artifacts-9.0.120-1.el9_8
redhat/dotnet-sdk<9.0-source-built-artifacts-9.0.120-1.el9_8
9.0-source-built-artifacts-9.0.120-1.el9_8
redhat/dotnet-sdk<9.0-source-built-artifacts-9.0.120-1.el9_8.aa
9.0-source-built-artifacts-9.0.120-1.el9_8.aa
redhat/dotnet-sdk<9.0-source-built-artifacts-9.0.120-1.el9_8
9.0-source-built-artifacts-9.0.120-1.el9_8

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/dotnet9.0 to a version that resolves this vulnerability.

    Fixed in 9.0.120-1.el9_8
  2. Upgrade

    Upgrade redhat/aspnetcore-runtime to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  3. Upgrade

    Upgrade redhat/aspnetcore-runtime-dbg to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  4. Upgrade

    Upgrade redhat/aspnetcore-targeting-pack to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  5. Upgrade

    Upgrade redhat/dotnet-apphost-pack to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  6. Upgrade

    Upgrade redhat/dotnet-apphost-pack to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.19-1.el9_8
  7. Upgrade

    Upgrade redhat/dotnet-hostfxr to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  8. Upgrade

    Upgrade redhat/dotnet-hostfxr to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.19-1.el9_8
  9. Upgrade

    Upgrade redhat/dotnet-runtime to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  10. Upgrade

    Upgrade redhat/dotnet-runtime to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.19-1.el9_8
  11. Upgrade

    Upgrade redhat/dotnet-runtime-dbg to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  12. Upgrade

    Upgrade redhat/dotnet-sdk to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8
  13. Upgrade

    Upgrade redhat/dotnet-sdk to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.120-1.el9_8
  14. Upgrade

    Upgrade redhat/dotnet-sdk-aot to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8
  15. Upgrade

    Upgrade redhat/dotnet-sdk-aot to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.120-1.el9_8
  16. Upgrade

    Upgrade redhat/dotnet-sdk-dbg to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8
  17. Upgrade

    Upgrade redhat/dotnet-targeting-pack to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8
  18. Upgrade

    Upgrade redhat/dotnet-templates to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8
  19. Upgrade

    Upgrade redhat/dotnet9.0-debuginfo to a version that resolves this vulnerability.

    Fixed in 9.0.120-1.el9_8
  20. Upgrade

    Upgrade redhat/dotnet9.0-debugsource to a version that resolves this vulnerability.

    Fixed in 9.0.120-1.el9_8
  21. Upgrade

    Upgrade redhat/netstandard-targeting-pack to a version that resolves this vulnerability.

    Fixed in 2.1-9.0.120-1.el9_8
  22. Upgrade

    Upgrade redhat/aspnetcore-runtime to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  23. Upgrade

    Upgrade redhat/aspnetcore-runtime-dbg to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  24. Upgrade

    Upgrade redhat/aspnetcore-targeting-pack to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  25. Upgrade

    Upgrade redhat/dotnet-apphost-pack to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  26. Upgrade

    Upgrade redhat/dotnet-apphost-pack to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.19-1.el9_8.aa
  27. Upgrade

    Upgrade redhat/dotnet-hostfxr to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  28. Upgrade

    Upgrade redhat/dotnet-hostfxr to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.19-1.el9_8.aa
  29. Upgrade

    Upgrade redhat/dotnet-runtime to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  30. Upgrade

    Upgrade redhat/dotnet-runtime to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.19-1.el9_8.aa
  31. Upgrade

    Upgrade redhat/dotnet-runtime-dbg to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  32. Upgrade

    Upgrade redhat/dotnet-sdk to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8.aa
  33. Upgrade

    Upgrade redhat/dotnet-sdk to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.120-1.el9_8.aa
  34. Upgrade

    Upgrade redhat/dotnet-sdk-aot to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8.aa
  35. Upgrade

    Upgrade redhat/dotnet-sdk-aot to a version that resolves this vulnerability.

    Fixed in 9.0-debuginfo-9.0.120-1.el9_8.aa
  36. Upgrade

    Upgrade redhat/dotnet-sdk-dbg to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8.aa
  37. Upgrade

    Upgrade redhat/dotnet-targeting-pack to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.19-1.el9_8.aa
  38. Upgrade

    Upgrade redhat/dotnet-templates to a version that resolves this vulnerability.

    Fixed in 9.0-9.0.120-1.el9_8.aa
  39. Upgrade

    Upgrade redhat/dotnet9.0-debuginfo to a version that resolves this vulnerability.

    Fixed in 9.0.120-1.el9_8.aa
  40. Upgrade

    Upgrade redhat/dotnet9.0-debugsource to a version that resolves this vulnerability.

    Fixed in 9.0.120-1.el9_8.aa
  41. Upgrade

    Upgrade redhat/netstandard-targeting-pack to a version that resolves this vulnerability.

    Fixed in 2.1-9.0.120-1.el9_8.aa
  42. Upgrade

    Upgrade redhat/dotnet-sdk to a version that resolves this vulnerability.

    Fixed in 9.0-source-built-artifacts-9.0.120-1.el9_8
  43. Upgrade

    Upgrade redhat/dotnet-sdk to a version that resolves this vulnerability.

    Fixed in 9.0-source-built-artifacts-9.0.120-1.el9_8.aa
  44. Upgrade

    Upgrade .NET 9.0 (SDK and Runtime) to a version that resolves this vulnerability.

    Fixed in 9.0.120
  45. Upgrade

    Upgrade .NET 9.0 Runtime to a version that resolves this vulnerability.

    Fixed in 9.0.19
  46. Compensating control

    If you cannot immediately apply the RHEL 9.8.z .NET 9.0 update (JIRA:RHEL-235476), review and apply the workaround/mitigation guidance referenced by the advisory at access.redhat.com/articles/11258 for CVE-2026-62899, CVE-2026-62901, CVE-2026-62909, and CVE-2026-62900.

Event History

Aug 17, 2026
Advisory Published
via Red Hat·12:00 AM
Data Sourced
via Red Hat·12:00 AM
RemedyDescriptionAffected Software

Frequently Asked Questions

1

Which deployments should be prioritized for this update?

Systems using the listed Red Hat .NET 9.0 SDK, runtime, ASP.NET Core runtime, hostfxr, apphost, targeting-pack, or debug packages are in scope. The advisory applies to the RHEL 9.8.z update stream.

2

What types of security impact are addressed?

The update addresses four security issues: a security feature bypass, information disclosure, denial of service, and elevation of privilege vulnerability. The provided advisory does not specify attack prerequisites, affected configurations, or exploit conditions for the individual CVEs.

3

What remediation is provided?

Update .NET 9.0 to SDK version 9.0.120 and Runtime version 9.0.19. The advisory provides no alternative mitigations for environments where patching must be deferred.

Company

Resources

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