CVE-2026-70179: ASP.NET Core Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 7.5)

CVSS Vector

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

Category

Elevation of Privilege

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Oct

Released

2026-10-13

Description

Authentication bypass by spoofing in ASP.NET Core allows an authorized attacker to elevate privileges over a network.

FAQ

What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain ELEVATED privileges, which may allow them to perform actions beyond their original permissions. According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to have a deep understanding of the system and the ability to manipulate its components to trigger a specific condition. Successful exploitation is not guaranteed and depends on a combination of factors that may include the environment, system configuration, and the presence of additional security measures.

Affected Products (11)

Developer Tools

• Microsoft Visual Studio 2026 version 18.10
• Microsoft Visual Studio 2022 version 17.14

Other

• Microsoft.AspNetCore.Authentication.Negotiate on .NET 10.0 installed on Windows
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 10.0 installed on Linux
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 10.0 installed on Mac OS
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 8.0 installed on Windows
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 8.0 installed on Linux
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 8.0 installed on Mac OS
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 9.0 installed on Windows
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 9.0 installed on Linux
• Microsoft.AspNetCore.Authentication.Negotiate on .NET 9.0 installed on Mac OS

Security Updates (1)

• Release Notes

Acknowledgments

thegoldmandm

Revision History

• 2026-10-13: Information published.