Microsoft Security Advisory CVE-2026-26131 – .NET Elevation of Privilege Vulnerability

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 10.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

An elevation of privilege vulnerability exists in .NET due to improper authorization. Incorrect packaging permissions could allow an attacker to gain elevated privileges.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/386

CVSS Details

• Severity: High
• Version: 3.1
• Score: 7.8
• Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
• Weakness: CWE-276 (Incorrect Default Permissions)

Affected Platforms

• Platforms: Linux
• Architectures: All

Affected Products

<a name=".NET 10"></a>.NET 10

Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.NetCore.App.Runtime.linux-arm | >= 10.0.0, <= 10.0.3 | 10.0.4 Microsoft.NetCore.App.Runtime.linux-arm64 | >= 10.0.0, <= 10.0.3 | 10.0.4 Microsoft.NetCore.App.Runtime.linux-musl-arm | >= 10.0.0, <= 10.0.3 | 10.0.4 Microsoft.NetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0, <= 10.0.3 | 10.0.4 Microsoft.NetCore.App.Runtime.linux-musl-x64 | >= 10.0.0, <= 10.0.3 | 10.0.4 Microsoft.NetCore.App.Runtime.linux-x64 |...