MicrosoftCVE-2026-62871

Microsoft .NET 8.0 runtime: out-of-bounds write

Microsoft

CVE-2026-62871 · Published Aug 11, 2026 · updated Oct 28, 2026

High7.8

Fix: upgrade to 8.0.30 or later (4 fixed versions below)

Microsoft advisory

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

Affected versions

Package	Affected	Fixed in
.NET 8.0 runtime Product	>= 8.0.0, < 8.0.30	8.0.30
.NET 9.0 runtime Product	>= 9.0.0, < 9.0.19	9.0.19
Microsoft Visual Studio 2022 version 17.14 Product	>= 17.14.0, < 17.14.38	17.14.38
Microsoft Visual Studio 2026 version 18.8 Product	>= 18.0, < 18.8.3	18.8.3

Changes since it was listed

Fixed inNov 3Fixed in: .NET 8.0 8.0.30, .NET 9.0 9.0.19, Microsoft Visual Studio 2022 version 17.14 17.14.38 to .NET 8.0 runtime 8.0.30, .NET 9.0 runtime 9.0.19, Microsoft Visual Studio 2022 version 17.14 17.14.38

Details and references

CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Severity from: the vendor (its own CVE record or advisory)
Weakness: CWE-122, CWE-787

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