CVE-2026-47300: ASP.NET Core Elevation of Privilege Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-14 · updated 2026-10-28
Weakness: CWE-303

Description

Incorrect implementation of authentication algorithm in ASP.NET Core allows an authorized attacker to elevate privileges over a network.

Affected products

Microsoft .NET: from 8.0.0 before 8.0.29; from 9.0.0 before 9.0.18; from 10.0.0 before 10.0.6 — fixed in 8.0.29, 9.0.18, 10.0.6
Microsoft Visual Studio 2022 version 17.14: from 17.12.0 before 17.12.22; from 17.14.0 before 17.14.36 — fixed in 17.12.22, 17.14.36
Microsoft Visual Studio 2026 version 18.9: from 18.7.0 before 18.7.4 — fixed in 18.7.4
Microsoft .NET 10.0 runtime: from 10.0.0 before 10.0.10 — fixed in 10.0.10
Microsoft .NET 8.0 runtime: from 8.0.0 before 8.0.29 — fixed in 8.0.29
Microsoft .NET 9.0 runtime: from 9.0.0 before 9.0.18 — fixed in 9.0.18
Microsoft Visual Studio 2026 version 18.7: from 18.0 before 18.7.4 — fixed in 18.7.4
Microsoft Visual Studio 2022 version 17.14: from 17.12.0 before 17.12.22 — fixed in 17.12.22

How to fix

Upgrade to a fixed version: Microsoft .NET 8.0.29, 9.0.18, 10.0.6; Microsoft Visual Studio 2022 version 17.14 17.12.22, 17.14.36; Microsoft Visual Studio 2026 version 18.9 18.7.4; Microsoft .NET 10.0 runtime 10.0.10; Microsoft .NET 8.0 runtime 8.0.29; Microsoft .NET 9.0 runtime 9.0.18; Microsoft Visual Studio 2026 version 18.7 18.7.4; Microsoft Visual Studio 2022 version 17.14 17.12.22. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-47300

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