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CVE-2026-88092

Microsoft Security Advisory CVE-2026-88092 - ASP.NET Core Security Feature Bypass Vulnerability

Published Oct 13, 2026 · updated Oct 13, 2026 · Microsoft ASP.NET Core 10.0

## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. An aborted Kestrel HTTP/1 connection can reparse unread request-body bytes as another request, creating a request-smuggling or desynchronization path. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/472 ## CVSS Details - **Version:** 3.1 - **Severity:** Critical - **Score:** 9.4 - **Vector:** - **Weakness:** CWE-444 (Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')) ## Affected Platforms - **Platforms:** Windows, Linux, macOS - **Architectures:** All ## Affected Packages The vulnerability affects Microsoft .NET projects that use an affected package version listed below. Package name | Affected version | Patched version ------------ | ---------------- | --------------- [Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, How do I know if I am affected? If using a package listed in [affected packages](#affected-packages), you're exposed to the vulnerability. ### How do I fix the issue? 1. To fix the issue please install the latest version of .NET. If you have installed on

Timeline

Detection, updates, and resolution for this record.

  1. Oct 13, 2026 · Catalog

    Detected

    ## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. An aborted Kestrel HTTP/1 connection can reparse unread request-body bytes as another request, creating a request-smuggli

  2. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-arm fixed in 8.0.32; Microsoft.AspNetCore.App.Runtime.linux-arm64 fixed in 8.0.32; Microsoft.AspNetCore.App.Runtime.linux-musl-arm fixed in 8.0.32; Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 fixed in 8.0.32

  3. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-arm 8.0.0 → 8.0.32

  4. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-arm64 8.0.0 → 8.0.32

  5. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm 8.0.0 → 8.0.32

  6. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 8.0.0 → 8.0.32

  7. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-x64 8.0.0 → 8.0.32

  8. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-x64 8.0.0 → 8.0.32

  9. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.osx-arm64 8.0.0 → 8.0.32

  10. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.osx-x64 8.0.0 → 8.0.32

  11. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.win-arm64 8.0.0 → 8.0.32

  12. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.win-x64 8.0.0 → 8.0.32

  13. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.win-x86 8.0.0 → 8.0.32

  14. Oct 13, 2026 · Catalog

    Fix available

    NuGet Microsoft.AspNetCore.App.Runtime.linux-arm 10.0.0 → 10.0.13

  15. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-arm fixed in 8.0.32

  16. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-arm64 fixed in 8.0.32

  17. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-musl-arm fixed in 8.0.32

  18. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 fixed in 8.0.32

  19. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-musl-x64 fixed in 8.0.32

  20. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-x64 fixed in 8.0.32

  21. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.osx-arm64 fixed in 8.0.32

  22. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.osx-x64 fixed in 8.0.32

  23. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.win-arm64 fixed in 8.0.32

  24. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.win-x64 fixed in 8.0.32

  25. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.win-x86 fixed in 8.0.32

  26. Oct 13, 2026 · GitHub Advisory Database

    Fix available

    Microsoft.AspNetCore.App.Runtime.linux-arm fixed in 10.0.13

  27. Oct 13, 2026 · Catalog

    Updated

    ## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. An aborted Kestrel HTTP/1 connection can reparse unread request-body bytes as another request, creating a request-smuggli

Affected

  • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm10.0.0 → 10.0.13
  • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm8.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm8.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-x648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.linux-x648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.osx-arm648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.osx-x648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.win-arm648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.win-x648.0.0 → 8.0.32
  • NuGet Microsoft.AspNetCore.App.Runtime.win-x868.0.0 → 8.0.32
  • vendor Microsoft ASP.NET Core 10.0version unspecified

Sources

  • CVE.orgCVE-2026-88092

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

    cve.org
  • GitHub Advisory DatabaseGHSA-rv87-ccxw-8ggf

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • OSV.devGHSA-rv87-ccxw-8ggf

    Microsoft Security Advisory CVE-2026-88092 - ASP.NET Core Security Feature Bypass Vulnerability

    osv.dev

References