lldb fails to attach to running application

Steps to reproduce:

• create a simple Qt GUI application with Creator
• build this application with a Kit using Qt5 and the lldb engine
• run the built application from commandline
• trigger 'Debug' -> 'Start Debugging' -> 'Attach to Running Application...' and choose the used kit and the started application

Current result:

• Creator/lldb fails to get the executable for this process

Expected result:

• attaching to an application built with exactly the same kit should work