Security Bypass Affecting microsoft.netcore.app package, versions [,2.1.22)[3.0.0,3.1.8)


Severity

Recommended
0.0
high
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
17.33% (95th percentile)

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  • Snyk IDSNYK-DOTNET-MICROSOFTNETCOREAPP-610168
  • published9 Sept 2020
  • disclosed8 Sept 2020
  • creditMatt Langlois of Github Security Team

Introduced: 8 Sep 2020

CVE-2020-1045  (opens in a new tab)
CWE-358  (opens in a new tab)

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.

CVSS Base Scores

version 3.1