Consider the following scenario:
You deploy some public folder databases in a Microsoft Exchange Server 2010 environment that has Exchange Server 2010 Service Pack 3 (SP3) installed.
You use an application that performs a CONVENIENT_DEPTH query against public folders.
In this scenario, other tenant's subfolders are returned even though you do not have the permission to see these tenant's parent folders.
This issue occurs because the CONVENIENT_DEPTH flag can traverse the folders that you do not have permissions for. Therefore, the flag can retrieve the hierarchy table of all public folders that you have permissions to see.
To resolve this issue, install the following update rollup:
2891587 Description of Update Rollup 3 for Exchange Server 2010 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the CONVENIENT_DEPTH flag, go to the following Microsoft website: