Summary: Under certain conditions a user might inadvertently store the credentials (such as username and password) for a data source (such as a database login) in a workbook. See this KB article for more information.
Vulnerable Versions: Tableau Desktop 8.2 (through 8.2.13), 8.3 (through 8.3.8), 9.0 (through 9.0.4)
Tableau Server 8.2 (through 8.2.13), 8.3 (through 8.3.8), 9.0 (through 9.0.4)
Resolution: The issue can be fixed by upgrading to the following Tableau Server or Tableau Desktop versions:
Tableau Desktop 8.2.14
Tableau Desktop 8.3.9
Tableau Server 9.0.5