CVE-2026-70196: Microsoft Security Advisory CVE-2026-70196 - ASP.NET Core Denial of Service Vulnerability

October 13, 2026 (updated October 19, 2026)

Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.WebUtilities. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Incrementally arriving form data can cause FormPipeReader to repeatedly rescan the full buffered body, resulting in quadratic CPU consumption and denial of service.

References

github.com/advisories/GHSA-57xr-hfxx-jw5x
github.com/dotnet/announcements/issues/465
github.com/dotnet/aspnetcore/discussions/69799
github.com/dotnet/aspnetcore/security/advisories/GHSA-57xr-hfxx-jw5x
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70196
nvd.nist.gov/vuln/detail/CVE-2026-70196

Code Behaviors & Features

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