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Findings

CVE-2026-70159

Microsoft Security Advisory CVE-2026-70159 - ASP.NET Core Denial of Service Vulnerability

Published Oct 13, 2026

Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.SignalR.Common and Microsoft.AspNetCore.SignalR.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. SignalR stateful reconnect clients can indefinitely block broadcasts through MessageBuffer.ResendAsync backpressure and retain associated resources.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 13, 2026 · GitLab Advisory Database

    Detected

    Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.SignalR.Common and Microsoft.AspNetCore.SignalR.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. SignalR stateful reconnect clients can indefinitely block broadcasts through MessageBuffer.ResendAsync backpr

Affected

  • nuget microsoft.aspnetcore.signalr.commonversion unspecified
  • nuget microsoft.aspnetcore.signalr.coreversion unspecified

Sources

  • CVE.orgCVE-2026-70159

    Official CVE identifier

    cve.org
  • FIRST EPSSCVE-2026-70159

    30-day exploitation probability 1.1%

    first.org
  • GitLab Advisory DatabaseCVE-2026-70159

    Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.SignalR.Common and Microsoft.AspNetCore.SignalR.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. SignalR stateful reconnect clients can indefinitely block broadcasts through MessageBuffer.ResendAsync backpr

    advisories.gitlab.com