The patterns on your pics look very much like the patterns discussed
here, therefore yes, this looks like a light leak.
In order to locate the point of entry, check which side of your film is affected, and where this side is when the film is in the camera. The camera lens flips left&right and up&down, so from the subject matter on your negs it should be easy to determine which side was left/up during exposure and therefore where light came in. There a shops which sell replacement light seals.