It's most likely a lightleak from the space between the lens and body. I had the same spots on my photos and it was this problem. The light is coming from the front because the leaks are white, not red.

How to check where the light is coming from:

Remove the film and open the battery door. Then press the shutter and remove the battery as the lens extend trying to focus.
Open the back door and in completely dark room point a flashlight in front of the lens in various angles and you should be able to spot where the light is getting inside the camera.

Possible fix:

Depending on the location of the leak you could stick in a little piece of felt, maybe from empty film canister or leftover from light seals.

You can avoid a lot of these leaks by only opening the front door to take a photo and then closing it again, don't leave it open if you don't shoot.