I would try to contact the manufacturer and see what they used to begin with. If you can't get an answer that way, then I would probably try contact cement, but it will be tough without having the entire piece of veneer taken off.
Loose Veneer, best Fix?
Some of the veneer is coming loose on the edges/corners of my speakers. Looks like it was originally applied with contact cement. Any one had this problem? What's the best glue and method for repair? Thanks!