Symptoms
Assume that you use Dynamic Data Masking (DDM) on a column in a table in Microsoft SQL Server 2016 or 2017 to mask sensitive data. Masked data can be exposed when a query manipulates the data using a temporary table.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Resolution
This issue is fixed in the following cumulative updates for SQL Server:
About cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
References
Learn about the terminology that Microsoft uses to describe software updates.