It depends a bit on what you mean by “stealing”
If you were to break into the coke vault, hack into their computers, threaten or blackmail a coke executive, etc. in order to obtain it, those would all be illegal acts on their own.
But if you reverse-engineered the recipe yourself, or just happened to come across it in some legal fashion you could do pretty much whatever you want with it- publish the recipe, make your own cola and sell it (can’t call it “coca-cola” or “Coke” though because of trademarks and such,) try to sell the recipe to one of Coke’s competitors, etc.
Anyone with the recipe is going to have a hell of a time trying to do anything with it though because one of the ingredients is allegedly still coca leaf extract and coke is pretty much the only entity that is allowed to do anything with the stuff.
My friend and her husband got a switch back when it first launched, I had heard about this and so the next time I was over I asked if they’d licked one yet.
He said they hadn’t, and he also denied my request to lick one.
When he left the room, his wife got a mischievous look in her eye and asked if I wanted to lick one.
I of course took her up on her offer and tasted a cartridge while he wasn’t looking.
I asked if she had tried one, and of course she had.
They’re both cool people, but of the two of them she’s definitely my partner in crime.