MessagePack-CSharp Denial of Service Vulnerability

Source data

Overview

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

Impact & technical details

Denial of Service

CVSS base score

5.3 / 10

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Highest base score supplied by MSRC for this record; the vector belongs to that score. Ratings can vary by product. Microsoft Important is displayed as High; Moderate is displayed as Medium.

Affected products

• Microsoft Edge (Chromium-based)
• Microsoft Visual Studio 2022 version 17.14
• Microsoft Visual Studio 2026 version 18.10
• Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 11.0 runtime installed on Linux
• Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 11.0 runtime installed on Mac OS
• Microsoft.AspNetCore.SignalR.Protocols.MessagePack on .NET 11.0 runtime installed on Windows
• System.Formats.Cbor on .NET 10.0 runtime installed on Linux
• System.Formats.Cbor on .NET 10.0 runtime installed on Mac OS

Source guidance

Remediation

• Release Notes

At least one Microsoft vendor-fix reference is available. Check each affected product for its applicable update, prerequisites, and supported version.

Authoritative sources & updates

Findings and update information come from the linked publishers. GTP compiles the public record and provides the recommendation above. CVSS ratings shown here come from Microsoft. NVD references provide additional public context.

• Microsoft Security Response Center (opens in a new tab)
• Microsoft security update · Release Notes (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• Microsoft security update · Release Notes (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)