Security Bypass Affecting microsoft.netcore.app Open this link in a new tab package, versions [,2.1.22) [3.0.0,3.1.8)


0.0
high
  • Exploit Maturity

    Proof of concept

  • Attack Complexity

    Low

  • Integrity

    High

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  • snyk-id

    SNYK-DOTNET-MICROSOFTNETCOREAPP-610168

  • published

    9 Sep 2020

  • disclosed

    8 Sep 2020

  • credit

    Matt Langlois of Github Security Team

How to fix?

Upgrade Microsoft.NETCore.App to version 2.1.22, 3.1.8 or higher.

Overview

Microsoft.NETCore.App is a set of .NET API's that are included in the default .NET Core application model.

Affected versions of this package are vulnerable to Security Bypass. The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded. The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names. This CVE also affects Microsoft.Owin due to it using a similar cookie parsing mechanism.