If well wrapped, it can keep for months without losing acceptable texture and taste. It won't be fresh bread, but it will be edible and useful as an ingredient in cooked dishes. While frozen it doesn't to go bad in the sense of becoming poisonous from bacterial growth, but over time it does lose its quality, and after six months or so you wouldn't want to eat it.
Vacuum packaging is best. Putting it into a resealable bag out of which you have drawn as much air as you can is second best.