Content spills out of boxes

Hi,

I am wondering how to stop the content spilling out over the bottom of the box. I have it set up so that it shows the featured image, all of varying sizes, then the title and then the excerpt and read more. However as the image sizes vary, the room that is left over underneath varies. Therefore some have room for only the title, whereas others have room for the title and excerpt and read more button. Is there a simple way of just cutting off the content? So that it only displays as much as fits in each box?

Thank you!