Assume that you have Microsoft SQL Server 2014, 2016 and 2017 installed. You have a table column that contains many null values, and you execute a query on that table by using the default Cardinality Estimator (CE). In this scenario, you may experience an overestimation in a filter that compares the table column to a value that's unknown at compile time.
This issue is fixed in the following updates for SQL Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.