Microsoft has released Security Updates (SUs) for vulnerabilities found in:
Exchange Server 2013
Exchange Server 2016
Exchange Server 2019
SUs are available in a self-extracting auto-elev...
Updated Sep 18, 2023
Version 9.0
Blog Post
It is worth noting that there continues to be two versions of the Exchange Security Updates - the msp from the Microsoft Update Catalog and the exe (msp wrapped to force elevated installation) - it's always in the article, but easy to miss.
I have personally installed using the msp at an elevated command prompt on forty-four Exchange 2016 servers and one Exchange 2019 server without issue (except for prompt on most servers relating to running third party backup service which I safely ignore) [N.B. Ensure PowerShell is not running].
Unattended installation is achieved from folder location with: msiexec /p Exchange2016-KB5022143-x64-en.msp /qb
https://www.catalog.update.microsoft.com/Home.aspx
SCCM (MECM) and Exchange Security Updates have not played nicely together for me in the past (with services issues at the end of the installation) and it was determined that the best way forward (for me at least) was to handle Exchange Security Updates separately with the above method.