CVE-2020-1045: Microsoft ASP.NET Core Security Feature Bypass Vulnerability

Overview

Severity
High (CVSS 7.5)
CVSS Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:P/RL:O/RC:C
Category
Security Feature Bypass
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2020-Sep
Released
2020-09-08
EPSS Score
20.40% (percentile: 95.5%)

Description

A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names. 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.

Affected Products (2)

Other

  • 11564
  • 11728

Security Updates (2)

Acknowledgments

Matt Langlois of Github Security Team

Revision History

  • 2020-09-08: Information published.