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

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-13 · updated 2026-10-31
Weakness: CWE-787

Description

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

Affected products

Microsoft .NET 10.0 installed on Linux: from 10.0.0 before 10.0.403 — fixed in 10.0.403
Microsoft .NET 10.0 installed on Mac OS: from 10.0.0 before 10.0.403 — fixed in 10.0.403
Microsoft .NET 10.0 installed on Windows: from 10.0.0 before 10.0.403 — fixed in 10.0.403
Microsoft .NET 10.0 runtime: from 10.0.0 before 10.0.13 — fixed in 10.0.13
Microsoft .NET 11.0 installed on Linux: from 11.0.0-preview.1 before 11.0.100-rc.3 — fixed in 11.0.100-rc.3
Microsoft .NET 11.0 installed on Mac OS: from 11.0.0-preview.1 before 11.0.100-rc.3 — fixed in 11.0.100-rc.3
Microsoft .NET 11.0 installed on Windows: from 11.0.0-preview.1 before 11.0.100-rc.3.26522.148 — fixed in 11.0.100-rc.3.26522.148
Microsoft .NET 11.0 runtime: from 11.0.0 before 11.0.0-rc.2 — fixed in 11.0.0-rc.2
Microsoft .NET 8.0 installed on Linux: from 8.0.0 before 8.0.427 — fixed in 8.0.427
Microsoft .NET 8.0 installed on Mac OS: from 8.0.0 before 8.0.427 — fixed in 8.0.427
Microsoft .NET 8.0 installed on Windows: from 8.0.0 before 8.0.427 — fixed in 8.0.427
Microsoft .NET 8.0 runtime: from 8.0.0 before 8.0.32 — fixed in 8.0.32
Microsoft .NET 9.0 installed on Linux: from 9.0.0 before 9.0.320 — fixed in 9.0.320
Microsoft .NET 9.0 installed on Mac OS: from 9.0.0 before 9.0.320 — fixed in 9.0.320
Microsoft .NET 9.0 installed on Windows: from 9.0.0 before 9.0.320 — fixed in 9.0.320
Microsoft .NET 9.0 runtime: from 9.0.0 before 9.0.21 — fixed in 9.0.21
Microsoft Visual Studio 2019 version 16.11: from 16.11.0 before 16.11.61 — fixed in 16.11.61
Microsoft Visual Studio 2026 version 18.10: from 18.10.0 before 18.10.4 — fixed in 18.10.4
Microsoft Visual Studio 2026 version 18.11: from 18.11.0 before 18.11.2 — fixed in 18.11.2
Microsoft Visual Studio 2026 version 18.12: from 18.12.0 before 18.12 Insiders 3 — fixed in 18.12 Insiders 3
Microsoft Visual Studio 2022 version 17.14: from 17.14.0 before 17.14.43 — fixed in 17.14.43

How to fix

Upgrade to a fixed version: Microsoft .NET 10.0 installed on Linux 10.0.403; Microsoft .NET 10.0 installed on Mac OS 10.0.403; Microsoft .NET 10.0 installed on Windows 10.0.403; Microsoft .NET 10.0 runtime 10.0.13; Microsoft .NET 11.0 installed on Linux 11.0.100-rc.3; Microsoft .NET 11.0 installed on Mac OS 11.0.100-rc.3; Microsoft .NET 11.0 installed on Windows 11.0.100-rc.3.26522.148; Microsoft .NET 11.0 runtime 11.0.0-rc.2; Microsoft .NET 8.0 installed on Linux 8.0.427; Microsoft .NET 8.0 installed on Mac OS 8.0.427; Microsoft .NET 8.0 installed on Windows 8.0.427; Microsoft .NET 8.0 runtime 8.0.32. Check the vendor advisory for mitigations.

In the news

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

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70197

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