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

Executive Summary

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

Overview

7.5

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Elevation of Privilege

Weakness CWE-290: Authentication Bypass by Spoofing

Released Oct 13 2026

Last Updated Oct 13 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

CVSS Vector

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 6.5

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

11 affected products

Product	KB Article	Severity	Impact	Restart Required
Microsoft Visual Studio 2022 version 17.14	`Release Notes (Security Update)`	Important	Elevation of Privilege	Yes
Microsoft Visual Studio 2026 version 18.10	`Release Notes (Security Update)`	Important	Elevation of Privilege	Yes
Microsoft.AspNetCore.Authentication.Negotiate on .NET 10.0 installed on Linux	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 10.0 installed on Mac OS	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 10.0 installed on Windows	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 8.0 installed on Linux	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 8.0 installed on Mac OS	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 8.0 installed on Windows	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 9.0 installed on Linux	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 9.0 installed on Mac OS	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown
Microsoft.AspNetCore.Authentication.Negotiate on .NET 9.0 installed on Windows	`Release Notes (Security Update)`	Important	Elevation of Privilege	Unknown

Patches

1 patch

Article	Type	Restart
`Release Notes`	Security Update	Yes

Exploits & PoC

No public exploit or PoC has been linked for this CVE yet. When available, references are sourced from public repositories and may be unverified or non-functional — review carefully before use.

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

thegoldmandm

References

MSRC Advisory MITRE NVD