Well, yes. Most hostels have guest kitchens, and indeed when I stayed in Vienna at one of the Wombat chain hostels, it had both a bar with food and drink, and a guest kitchen for people to prepare their own meals.
As a comment on the question said, it's very rare that hostels don't have kitchens for guests to use. They may be small, they may be underequipped, but there's usually some pots, pans and dishes. Sometimes you may have to pay a deposit to use them if there's been a history of them disappearing (Nomad hostel in Melbourne, Space Hotel in Melbourne) but there wasn't any problem in Vienna when I was there.
I have seen hostels without a kitchen, but it's pretty rare, and they're usually when I was trying to find the cheapest of the cheap - you get what you pay for, I guess.