Answer in brief
CVE-2026-45591 records a High severity (CVSS 7.5) vulnerability in ASP.NET Core Denial of Service Vulnerability. The current sources do not mark it as known exploited. The current feed maps Microsoft/ASP.NET Core 10.0 (generic), Microsoft/ASP.NET Core 8.0 (generic), Microsoft/ASP.NET Core 9.0 (generic), Microsoft/Microsoft Visual Studio 2026 version 18.6 (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2026-45591 records a High severity (CVSS 7.5) vulnerability in ASP.NET Core Denial of Service Vulnerability. The current sources do not mark it as known exploited. The current feed maps Microsoft/ASP.NET Core 10.0 (generic), Microsoft/ASP.NET Core 8.0 (generic), Microsoft/ASP.NET Core 9.0 (generic), Microsoft/Microsoft Visual Studio 2026 version 18.6 (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Microsoft/ASP.NET Core 10.0 (generic), Microsoft/ASP.NET Core 8.0 (generic), Microsoft/ASP.NET Core 9.0 (generic), Microsoft/Microsoft Visual Studio 2026 version 18.6 (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Microsoft/ASP.NET Core 10.0generic | >=10.0 <10.0.9 | 10.0.9 |
| Microsoft/ASP.NET Core 8.0generic | >=8.0 <8.0.28 | 8.0.28 |
| Microsoft/ASP.NET Core 9.0generic | >=9.0 <9.0.17 | 9.0.17 |
| Microsoft/Microsoft Visual Studio 2026 version 18.6generic | >=18.6.0 <18.6.3 | 18.6.3 |
| Microsoft/.NET 10.0generic | >=10.0.0 <10.0.9 | 10.0.9 |
| Microsoft/.NET 8.0generic | >=8.0.0 <8.0.28 | 8.0.28 |
| Microsoft/.NET 9.0generic | >=9.0.0 <9.0.17 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-x64nuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.App.Runtime.linux-x64nuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-x64nuget | >=10.0.0,<=10.0.8 | 10.0.9 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64nuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64nuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64nuget | >=10.0.0,<=10.0.8 | 10.0.9 |
| Microsoft.AspNetCore.App.Runtime.win-x64nuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.App.Runtime.win-x64nuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.win-x64nuget | >=10.0.0,<=10.0.8 | 10.0.9 |
| Microsoft.AspNetCore.SignalR.Protocols.MessagePacknuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.SignalR.Protocols.MessagePacknuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.SignalR.Protocols.MessagePacknuget | >=10.0.0,<=10.0.8 | 10.0.9 |
Published upstream
Jun 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
A flaw was found in ASP.NET Core SignalR and Blazor Server. A remote attacker could send a specially crafted MessagePack payload containing deeply nested arrays that trigger excessive recursion and cause a stack overflow. This issue may result in application termination and a denial of service condition
Quoted source text, attributed separately from HOL analysis.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Microsoft/ASP.NET Core 10.0 (generic), Microsoft/ASP.NET Core 8.0 (generic), Microsoft/ASP.NET Core 9.0 (generic), Microsoft/Microsoft Visual Studio 2026 version 18.6 (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Microsoft/ASP.NET Core 10.0generic | >=10.0 <10.0.9 | 10.0.9 |
| Microsoft/ASP.NET Core 8.0generic | >=8.0 <8.0.28 | 8.0.28 |
| Microsoft/ASP.NET Core 9.0generic | >=9.0 <9.0.17 | 9.0.17 |
| Microsoft/Microsoft Visual Studio 2026 version 18.6generic | >=18.6.0 <18.6.3 | 18.6.3 |
| Microsoft/.NET 10.0generic | >=10.0.0 <10.0.9 | 10.0.9 |
| Microsoft/.NET 8.0generic | >=8.0.0 <8.0.28 | 8.0.28 |
| Microsoft/.NET 9.0generic | >=9.0.0 <9.0.17 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-x64nuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.App.Runtime.linux-x64nuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-x64nuget | >=10.0.0,<=10.0.8 | 10.0.9 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64nuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64nuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64nuget | >=10.0.0,<=10.0.8 | 10.0.9 |
| Microsoft.AspNetCore.App.Runtime.win-x64nuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.App.Runtime.win-x64nuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.App.Runtime.win-x64nuget | >=10.0.0,<=10.0.8 | 10.0.9 |
| Microsoft.AspNetCore.SignalR.Protocols.MessagePacknuget | >=8.0.0,<=8.0.27 | 8.0.28 |
| Microsoft.AspNetCore.SignalR.Protocols.MessagePacknuget | >=9.0.0,<=9.0.16 | 9.0.17 |
| Microsoft.AspNetCore.SignalR.Protocols.MessagePacknuget | >=10.0.0,<=10.0.8 | 10.0.9 |
Published upstream
Jun 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
A flaw was found in ASP.NET Core SignalR and Blazor Server. A remote attacker could send a specially crafted MessagePack payload containing deeply nested arrays that trigger excessive recursion and cause a stack overflow. This issue may result in application termination and a denial of service condition
Quoted source text, attributed separately from HOL analysis.