She was young. I haven't seen any word on what happened, though she had "health problems" that prevented her from touring last year, or so I read. One never knows which bits are true.
Slartibartfast's Zombie link is playing as I type. I have chills. Believe it or not, I don't think I've heard that song other than I knew the song by the title only.
I indeed had not heard of her death until I read your question. I'm still in shock - - thought of her a lot since I read your question. I listened ot one of the Cranberries albums all the way through. Took the time to just listen. Oh, my.