What can cause bad taste in mouth after wisdom tooth extraction?

EXT > bad taste? Lots of possibilities: many patients just don't brush and floss as well after surgery, food decaying in socket, early infection, beginning of dry socket, etc. Make sure you are brushing and flossing adequately, rinsing after the first 24 hours and see your own dentist to check on healing.
Infection ? Dry socket ? Sutures with bacteria ? These are all guesses, and that's not what you want. Call your surgeon to discuss your concerns.
Dry socket. There are risks associated with wisdom tooth removal like with any other surgery. The dry socket is the most common complication that characterized by dull, aching pain and a bad smell or taste coming from the empty tooth socket. See your dentist for post-op evaluation and dry socket treatment if needed. .