Microsoft is releasing this security advisory to provide information about a vulnerability in .NET Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Microsoft is aware of a remote code execution vulnerability exists in .NET software when the software fails to check the source markup of an XML file. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user.

A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to an ASP.NET Core application, or other application that parses certain types of XML.

The security update addresses the vulnerability by restricting the types that are allowed to be present in the XML payload

Getting the Update