Since water comes from the outside to the inside...we need to see the outside. As the comment above, you can install flashing under the lip of the vinyl siding to coax the water outward, or you can fix the actual problem. Many times vinyl siding is just hiding the real issue. You have an outside seal that has failed somehow. If this is a new thing and it is just a failed seal, it should be simple to fix. If there is bad wood or a structural defect under the siding....that can get a bit more complex. either way, water is your enemy, and you need to get it addressed ASAP. The longer you go, the more expensive it will be.

Best thing you can do here. Good luck, and let us know how it comes out. They likely just jammed it with caulk, and that eventually fails. A contractor should be able to fix it right at a reasonable price. Now go and play pinball.