Typical American-style cabinet doors include a lumber raised panel center surrounded with 4 lumber pieces called stiles & rails. It is possible the center panel is a flat plywood panel.

The design is not strong and frequently breaks where the horizontal rails meet the vertical stiles. The problem comes from slamming the doors hard, leaning on them while reaching into lower cabinets, or small kids climbing on them while reaching upper cabinets. The larger the door the more the chance of fracture. ... or we could say the more kids in the home!

Sometimes the fracture also splits out on the front side along the shaped inner edge of the stile. That can be a cost raising factor.

The repair is to properly glue and clamp the shattered area/s; but, all such gluing must be done with proper wood glue and clamps!

Finally, in order to add additional strength to the previously broken door we add a small 1/4" thick matching wood splint block on the back sides where broken. It is about the size of a match book.

If the door is from a furniture piece, like an armoire, we don't add the block but add a special small headed long screw thru the side edge of the door thru the stile into the rail.

The typical cost to repair is $80 to $200 but is usually $110 with limited finish touchup.
Repairs including the front face could be slightly more.