Cabernet is a type of wine. If you incorrectly pronounce cabernet, as in you pronounce the "t" instead of make it silent, the word kind of sounds like "cabinet". A cabinet is a cupboard with shelves that you can lock. This joke is playing on the word Cabernet because it is a name of a wine and kind of sounds like cabinet if mispronounced.
You should lock up your wine in a cabernet .