CVE-2026-70197 .NET and Visual Studio Remote Code Execution Vulnerability

High 8.1 Published Updated

An out-of-bounds write in .NET allows remote attackers to execute arbitrary code, requiring immediate patching for all affected versions.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2026-70197?

CVE-2026-70197 is a high-severity memory corruption vulnerability in Microsoft .NET 10.0 installed on Linux, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Out-of-bounds write in .NET allows an unauthorized attacker to execute code over a network.

Weakness: CWE-787

Which versions are affected by CVE-2026-70197?

24 open source packages ship an affected version, including Microsoft.NETCore.App.Runtime.win-arm64, Microsoft.NETCore.App.Runtime.win-x64 and Microsoft.NETCore.App.Runtime.win-x86.

PackageAffectedFixed in
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 10.0.010.0.13
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 10.0.010.0.13
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 11.0.0-preview.111.0.0-rc.2
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 11.0.0-preview.111.0.0-rc.2
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 8.0.08.0.32
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 8.0.08.0.32
18 more packages
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 9.0.09.0.21
Microsoft.NETCore.App.Runtime.win-arm64 NuGetFrom 9.0.09.0.21
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 10.0.010.0.13
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 10.0.010.0.13
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 11.0.0-preview.111.0.0-rc.2
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 11.0.0-preview.111.0.0-rc.2
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 8.0.08.0.32
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 8.0.08.0.32
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 9.0.09.0.21
Microsoft.NETCore.App.Runtime.win-x64 NuGetFrom 9.0.09.0.21
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 10.0.010.0.13
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 10.0.010.0.13
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 11.0.0-preview.111.0.0-rc.2
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 11.0.0-preview.111.0.0-rc.2
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 8.0.08.0.32
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 8.0.08.0.32
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 9.0.09.0.21
Microsoft.NETCore.App.Runtime.win-x86 NuGetFrom 9.0.09.0.21

How do I fix CVE-2026-70197?

Upgrade Microsoft.NETCore.App.Runtime.win-arm64 to a fixed version for your release line: 10.0.13, 11.0.0-rc.2, 8.0.32 or 9.0.21.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-70197 being exploited?

There is no known exploitation of CVE-2026-70197 in the wild and no public exploit code.

Sources

Also known as GHSA-4mpw-cpwj-hxxj, UBUNTU-CVE-2026-70197.

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