Looks like a light leak to me. Is this the first time you've ever seen this?
Well actually I've seen it a couple of times with that specific camera. But it is only on some of the shots.. Could i fix the leak with tape... =
A camera can have a place where light will leak in some pictures but not others, depending on the location of the light source. Looks like yours is along the side (can't tell you right or left because I don't know how you turned the camera to get the vertical shot. Any horizontal shots with the light leak? If so, if the leak is on the right of the image, the leak will be on the left side of the camera, and it looks like where the back plate meets the main part of the camera.)
It's not hard to replace light seals. Open the back and check around the edges - is there any foam at all anywhere in the seams? You can get a sheet of black self-adhesive felt and cut a thin strip to place around the edges where the back meets the camera body. It's not hard and there are probably video tutorials that you might want to try for more detailed instruction.
I suppose tape might work (it would have to be black tape) but you'd have to re-tape every time you change rolls.