Description
Improper handling of highly compressed data (data amplification) in ASP.NET Core allows an unauthorized attacker to deny service over a network.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Microsoft | .NET 10.0 runtime | 10.0.0 – < 10.0.12 | 10.0.12 |
| Microsoft | .NET 8.0 runtime | 8.0.0 – < 8.0.31 | 8.0.31 |
| Microsoft | .NET 9.0 runtime | 9.0.0 – < 9.0.20 | 9.0.20 |
| Microsoft | ASP.NET Core 10.0 | 10.0 – < 10.0.12 | 10.0.12 |
| Microsoft | ASP.NET Core 11.0 | 11.0 – < 11.0 RC1 | 11.0 RC1 |
| Microsoft | ASP.NET Core 8.0 | 8.0 – < 8.0.31 | 8.0.31 |
| Microsoft | ASP.NET Core 9.0 | 9.0 – < 9.0.20 | 9.0.20 |
| Microsoft | Microsoft Visual Studio 2022 version 17.14 | 17.14.0 – < 17.14.40 | 17.14.40 |
| Microsoft | Microsoft Visual Studio 2026 version 18.9 | 18.9.0 – < 18.9.3 | 18.9.3 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | dotnet7 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | dotnet-hostfxr-8.0 +7 | 8.0.30-0.2.hum1 | RHSA-2026:74950 |
| Red Hat Hardened Images 1 | dotnet-hostfxr-9.0 +7 | 9.0.18-2.1.hum1 | RHSA-2026:74947 |
| Red Hat Hardened Images 1 | dotnet10.0 +5 | 10.0.112-1.hum1 | RHSA-2026:66863 |
| Red Hat Hardened Images 1 | dotnet8.0 +4 | 8.0.130-0.2.hum1 | RHSA-2026:74950 |
| Red Hat Hardened Images 1 | dotnet9.0 +6 | 9.0.119-2.1.hum1 | RHSA-2026:74947 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dotnet10-runtime | 10.0.12-r0 | — |
| Alpine v3.24 | dotnet8-runtime | 8.0.31-r0 | — |
| Alpine v3.24 | dotnet9-runtime | 9.0.20-r0 | — |
| Alpine v3.23 | dotnet10-runtime | 10.0.13-r0 | — |
| Alpine v3.23 | dotnet8-runtime | 8.0.31-r0 | — |
| Alpine v3.23 | dotnet9-runtime | 9.0.20-r0 | — |
| Alpine v3.22 | dotnet8-runtime | 8.0.31-r0 | — |
| Alpine v3.22 | dotnet9-runtime | 9.0.20-r0 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | aspnet-8-targeting-pack | 8.0.131-r0 | — |
| Wolfi rolling | dotnet-bootstrap-8 | 8.0.132-r0 | — |
| Wolfi rolling | dotnet-bootstrap-9 | 9.0.122-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| NuGet | Microsoft.AspNetCore.Server.IISIntegration | >= 11.0.0-preview.1, < 11.0.0-rc.1 | 11.0.0-rc.1 | GHSA-8cp2-47hg-mfgh |
| NuGet | Microsoft.AspNetCore.Server.IISIntegration | >= 8.0.0, < 8.0.31 | 8.0.31 | GHSA-8cp2-47hg-mfgh |
| NuGet | Microsoft.AspNetCore.Server.IISIntegration | >= 9.0.0, < 9.0.20 | 9.0.20 | GHSA-8cp2-47hg-mfgh |
| NuGet | Microsoft.AspNetCore.Server.IISIntegration | >= 10.0.0, < 10.0.12 | 10.0.12 | GHSA-8cp2-47hg-mfgh |
Advisories 6
- RHSA-2026:66863 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:74947 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2026:74950 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- WID-SEC-2026-3242 Microsoft Entwicklerwerkzeuge: Mehrere Schwachstellen ermöglichen Privilegieneskalation BSI CERT-Bund (WID) · Oct 6, 2026
- MSRC-CVE-2026-69304 ASP.NET Core Denial of Service Vulnerability Microsoft Security Response Center · Sep 25, 2026
- NCSC-2026-0351 Kwetsbaarheden verholpen in Microsoft Developer Tools NCSC-NL (Netherlands) · Sep 8, 2026
References
- ASP.NET Core Denial of Service Vulnerability vendor-advisory patch