CVE-2026-92707: MessagePack-CSharp Denial of Service Vulnerability

Overview

Severity
Medium (CVSS 5.3)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Category
Denial of Service
Exploit Status
Not Exploited
Publicly Disclosed
Yes
Patch Tuesday
2026-Oct
Released
2026-10-13

Description

Improperly controlled sequential memory allocation in .NET allows an unauthorized attacker to deny service over a network.

Affected Products (15)

Other

  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 10.0 installed on Windows
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 10.0 installed on Linux
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 10.0 installed on Mac OS
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 11.0 installed on Windows
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 11.0 installed on Linux
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 11.0 installed on Mac OS
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 8.0 installed on Windows
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 8.0 installed on Linux
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 8.0 installed on Mac OS
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 9.0 installed on Windows
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 9.0 installed on Linux
  • Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 9.0 installed on Mac OS

Developer Tools

  • Microsoft Visual Studio 2026 version 18.10
  • Microsoft Visual Studio 2022 version 17.14

Open Source Software

  • MessagePack 3.1.9

Security Updates (3)

Acknowledgments

Anonymous

Revision History

  • 2026-10-13: Information published.