Till it gets kicked out for having to low of a fee payment or you rbf
Discussion
How long does that take?
Depends on fee environment
Check around the 72 hr mark from initial tx. You should have a window of a couple hrs to rebroadcast. If you miss that window, try again in 72hrs. Made the low tx fee mistake twice recently and that's how it worked out for me. Eventually it will cancel on its own though. I let one ride out just to see and it was close to 2 weeks.