Microsoft has published a security advisory to address a vulnerability that is breaking email delivery on on-premises Microsoft Exchange servers. It is recommended that you take the necessary precautions by ensuring your products are always updated.
For more information on this update, you can follow the URL:
The Guyana National CIRT recommends that users and administrators review this update and apply it where necessary.
PDF Download: Microsoft Releases emergency fix for Exchange year 2022 Bug.pdf
Reference
https://thehackernews.com/2022/01/microsoft-issues-fix-for-exchange-y2k22.html