Microsoft .NET Framework 3.5 and 4.8
A remote code execution vulnerability exists in .NET software if the software fails to check the source markup of a file. An Authentication Bypass vulnerability exists in WCF and WIF that lets SAML tokens be signed by using arbitrary symmetric keys. This vulnerability enables an attacker to impersonate another user. The vulnerability exists in WCF, WIF 3.5 and later in .NET Framework, the WIF 1.0 component in Windows, the WIF Nuget package, and the WIF implementation in SharePoint. An information disclosure vulnerability exists if Exchange and Azure Active Directory allow the creation of entities by using Display Names that have non-printable characters.
To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE):
Known issues in this update
Microsoft is not currently aware of any issues in this update.
How to get this update
Install this update
To download and install this update, go to Settings > Update & Security > Windows Update, and then select Check for updates.
This update will be downloaded and installed automatically from Windows Update.
To get the standalone package for this update, go to the Microsoft Update Catalog website.
For a list of the files that are provided in this update, download the file information for cumulative update 4506990.
Additional information about this update
The following articles contain additional information about this update as it relates to individual product versions:
4507419 Description of the Cumulative Update for .NET Framework 3.5, 4.7.2, and 4.8 for Windows 10 Version 1809 and Windows Server 2019 (KB4507419)