Rust on the a-pillar

I have a 1999 Subaru Outback, and the paint is bubbling at the top corner of the windsheld on the drivers side. I can also see another rust spot developing beneath the paint in the center just along the top of the windshield. The rest of the car is in great shape, and the engine is under warranty for at least 80,000 more miles. Is this the kind of problem that kills an otherwise good car? Is this a safety concern for me and my passengers?