GHSA-fcg8-mg9g-6hc4
HIGH.NET Denial of Service Vulnerability
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Microsoft.AspNetCore.App.Runtime.win-x64.NETMicrosoft.AspNetCore.App.Runtime.win-x64.NETMicrosoft.AspNetCore.App.Runtime.win-x64.NETMicrosoft.AspNetCore.App.Runtime.linux-x64.NETMicrosoft.AspNetCore.App.Runtime.linux-x64.NETMicrosoft.AspNetCore.App.Runtime.linux-x64.NETMicrosoft.AspNetCore.App.Runtime.win-x86.NETMicrosoft.AspNetCore.App.Runtime.win-x86+25 moreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 6.0, .NET 5.0 and .NET Core 3.1. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
A vulnerability exists in .NET 6.0, .NET 5.0 and .NET core 3.1 where a malicious client can can cause a denial of service when HTML forms are parsed.
Affected software
- Any .NET 6.0 application running on .NET 6.0.4 or earlier.
- Any .NET 5.0 application running .NET 5.0.16 or earlier.
- Any .NET Core 3.1 application running on .NET Core 3.1.24 or earlier.
Affected packages
.NET Core 3.1
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.win-x64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.linux-arm | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.win-arm | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >=3.0.0,3.1.24 | 3.1.25 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >=3.0.0,3.1.24 | 3.1.25 |
.NET 5.0
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.win-x64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-arm | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.win-arm | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >=5.0.0,5.0.16 | 5.0.17 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >=5.0.0,5.0.16 | 5.0.17 |
.NET 6.0
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.AspNetCore.App.Runtime.win-x64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.linux-x64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.win-x86 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.osx-x64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.linux-arm64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.linux-arm | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.win-arm64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.win-arm | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.osx-arm64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >=6.0.0,6.0.4 | 6.0.5 |
| Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >=6.0.0,6.0.4 | 6.0.5 |
Patches
-
If you're using .NET Core 6.0, you should download and install Runtime 6.0.5 or SDK 6.0.105 (for Visual Studio 2022 v17.0) or SDK 6.0.203 (for Visual Studio 2022 v17.1) from https://dotnet.microsoft.com/download/dotnet-core/6.0.
-
If you're using .NET 5.0, you should download and install Runtime 5.0.17 or SDK 5.0.214 (for Visual Studio 2019 v16.9) or SDK 5.0.408 (for Visual Studio 2011 v16.11) from https://dotnet.microsoft.com/download/dotnet-core/5.0.
-
If you're using .NET Core 3.1, you should download and install Runtime 3.1.25 or SDK 3.1.419 (for Visual Studio 2019 v16.9 or Visual Studio 2011 16.11 or Visual Studio 2022 17.0 or Visual Studio 2022 17.1 ) from https://dotnet.microsoft.com/download/dotnet-core/3.1.
.NET 6.0, .NET 5.0 and .NET Core 3.1 updates are also available from Microsoft Update. To access this either type "Check for updates" in your Windows search, or open Settings, choose Update & Security and then click Check for Updates.
Other
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/222 An Issue for this can be found at https://github.com/dotnet/aspnetcore/issues/41609 MSRC details for this can be found at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-29145
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.win-x64 | ≥ 3.0.0&&< 3.1.25 | 3.1.25 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.win-x64 | ≥ 5.0.0&&< 5.0.17 | 5.0.17 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.win-x64 | ≥ 6.0.0&&< 6.0.5 | 6.0.5 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-x64 | ≥ 3.0.0&&< 3.1.25 | 3.1.25 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-x64 | ≥ 5.0.0&&< 5.0.17 | 5.0.17 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-x64 | ≥ 6.0.0&&< 6.0.5 | 6.0.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.AspNetCore.App.Runtime.win-x64. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Microsoft.AspNetCore.App.Runtime.win-x64 to 3.1.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fcg8-mg9g-6hc4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-fcg8-mg9g-6hc4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-fcg8-mg9g-6hc4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-fcg8-mg9g-6hc4 in your dependencies?
O3 detects GHSA-fcg8-mg9g-6hc4 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.