CVE-2026-62871: .NET Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 7.8)

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Aug

Released

2026-08-11

Last Updated

2026-09-21

EPSS Score

0.47% (percentile: 37.7%)

Description

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

FAQ

What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges. According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? Exploitation of this vulnerability requires that a user trigger the payload in the application.

Affected Products (4)

Developer Tools

• .NET 8.0 installed on Windows
• .NET 9.0 installed on Windows
• Microsoft Visual Studio 2026 version 18.8
• Microsoft Visual Studio 2022 version 17.14

Security Updates (2)

• 5122104
• 5122105

Acknowledgments

kai63001, <a href="https://x.com/ky0tofu">Ky0toFu</a>, 41ae55e9310ff27fa6f26af4727e5590, nono

Revision History

• 2026-08-11: Information published.
• 2026-08-13: Removed Linux and macOS products from the Affected Software table. This is an informational change only.
• 2026-09-21: Updated an acknowledgement. This is an informational change only.