It's well documented that in 5e, you can deal 0 (but not negative) damage on an attack roll, usually if you have a negative ability modifier. The same, presumably, would apply to spell damage.
A 1st-level Cure Wounds restores 1d8+spell mod in hit points. What happens if I have a -2 modifier, and roll a 1? Would it heal 0 hit points? Would it stabilize a dying character?
Official sources (including tweets from Crawford) preferred.