This security update resolves vulnerabilities in Microsoft Skype for Business Server and Microsoft Lync Server. To learn more about these vulnerabilities, see Microsoft Common Vulnerabilities and Exposures CVE-2021-26422 and Microsoft Common Vulnerabilities and Exposures CVE-2021-26421.
Improvements and fixes
This update also fixes the following issue:
Remote PowerShell cannot be connected after you install update 4470124 for Skype for Business 2019.
How to get and install the update
To get this update, install the following updates:
Security update deployment information
For deployment information about this update, see security update deployment information: May 11, 2021.
How to get help and support for this security update
Protect yourself online: Windows Security support
Learn how we guard against cyber threats: Microsoft Security