CVE-2026-70354: .NET Core Remote Code Execution Vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-11 · updated 2026-10-30
Weakness: CWE-787

Description

Out-of-bounds write in .NET allows an unauthorized attacker to execute code locally.

Affected products

Microsoft .NET: from 8.0.0 before 8.0.30; from 9.0.0 before 9.0.19; from 10.0.0 before 10.0.11 — fixed in 8.0.30, 9.0.19, 10.0.11
Microsoft .NET Framework: 3.5; 4.8.1, 4.8, 4.6.2, 4.7, 4.7.1, 4.7.2 (and their updates)
Microsoft Visual Studio 2022 version 17.14: from 17.14.0 before 17.14.38 — fixed in 17.14.38
Microsoft Visual Studio 2026 version 18.9: from 18.8.0 before 18.8.3 — fixed in 18.8.3
Microsoft .NET 10.0 runtime: from 10.0.0 before 10.0.11 — fixed in 10.0.11
Microsoft .NET 8.0 runtime: from 8.0.0 before 8.0.30 — fixed in 8.0.30
Microsoft .NET 9.0 runtime: from 9.0.0 before 9.0.19 — fixed in 9.0.19
Microsoft .NET Framework 3.5: from 3.5.0 before 2.0.50727.8984 & 3.0.30729.8980 — fixed in 2.0.50727.8984 & 3.0.30729.8980
Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2: from 3.0.0.0 before 2.0.50727.8984 & 3.0.30729.8980 & 4.7.4144.0 — fixed in 2.0.50727.8984 & 3.0.30729.8980 & 4.7.4144.0
Microsoft .NET Framework 3.5 AND 4.7.2: from 4.7.0 before 2.0.50727.9070 & 3.0.30729.9068 & 4.7.4144.0 — fixed in 2.0.50727.9070 & 3.0.30729.9068 & 4.7.4144.0
Microsoft .NET Framework 3.5 AND 4.8: from 4.8.0 before 2.0.50727.9070 & 3.0.30729.9068 & 4.8.4805.0 — fixed in 2.0.50727.9070 & 3.0.30729.9068 & 4.8.4805.0
Microsoft .NET Framework 3.5 AND 4.8.1: from 4.8.1 before 2.0.50727.9183 & 3.0.30729.9169 & 4.8.9343.0 — fixed in 2.0.50727.9183 & 3.0.30729.9169 & 4.8.9343.0
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2: from 4.7.0 before 4.7.4144.0 — fixed in 4.7.4144.0
Microsoft .NET Framework 4.8: from 4.8.0 before 4.8.4805.0 — fixed in 4.8.4805.0
Microsoft .NET Framework 4.8.1: from 4.8.0.0 before 4.8.9344.0 — fixed in 4.8.9344.0
Microsoft Visual Studio 2026 version 18.8: from 18.0 before 18.8.3 — fixed in 18.8.3
Microsoft Visual Studio 2022 version 17.14: from 17.14.0 before 17.14.38 — fixed in 17.14.38

How to fix

Upgrade to a fixed version: Microsoft .NET 8.0.30, 9.0.19, 10.0.11; Microsoft Visual Studio 2022 version 17.14 17.14.38; Microsoft Visual Studio 2026 version 18.9 18.8.3; Microsoft .NET 10.0 runtime 10.0.11; Microsoft .NET 8.0 runtime 8.0.30; Microsoft .NET 9.0 runtime 9.0.19; Microsoft .NET Framework 3.5 2.0.50727.8984 & 3.0.30729.8980; Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 2.0.50727.8984 & 3.0.30729.8980 & 4.7.4144.0; Microsoft .NET Framework 3.5 AND 4.7.2 2.0.50727.9070 & 3.0.30729.9068 & 4.7.4144.0; Microsoft .NET Framework 3.5 AND 4.8 2.0.50727.9070 & 3.0.30729.9068 & 4.8.4805.0; Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9183 & 3.0.30729.9169 & 4.8.9343.0; Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 4.7.4144.0. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70354

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