Microsoft released Windows 10 update KB4540673 two days ago on Patch Tuesday for versions 1903 and 1909. In that update, there was a security vulnerability in the SMBv3 (Microsoft Server Message Block version 3. The company acknowledged the flaw and shipped a new Cumulative Update KB4551762 for both the versions upgrading the build to 18362.720 for 1903 and 18363.720 for 1909.
For those who don’t know, SMBv3 (Server Message Block 3.0) is a network protocol that allows a computer’s client applications to read and write to files and to request services from servers in a computer network.
The update includes only the SMBv3 vulnerability fix.
Update KB4551762 highlight:
Updates a Microsoft Server Message Block 3.1.1 protocol issue that provides shared access to files and printers.
Fix and Improvement:
Security update to the Microsoft Server Message Block 3.1.1 (SMBv3).
It also comes with the same known issue included in the earlier update.
This update is mandatory; you download the update manually from here or can grab it via Windows Update, or after some time, it will install automatically.