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

October 13, 2026 (updated October 19, 2026)

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.

References

github.com/advisories/GHSA-rv87-ccxw-8ggf
github.com/dotnet/announcements/issues/472
github.com/dotnet/aspnetcore/security/advisories/GHSA-rv87-ccxw-8ggf
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88092
nvd.nist.gov/vuln/detail/CVE-2026-88092

Code Behaviors & Features

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