How do you repair a bubbled top on a veneer oak table top?

Inject epoxy using a syringe then apply a lot of weight over the area, 

make a small slit with a razor blade. then inject a small amount of glue (I use super glue) wipe off excess, then weight heavily or sometimes just heat will do it-use a soft cloth like a t-shirt (sometimes you have to wet it ) and press hard using a cloths iron.

DO NOT LET DEBRIS GET UNDER THE VENEER!!!!!!

afterwards keep dry

You might try using a damp towel and an electric iron.  The towel must not be WET just damp.  The iron should not be very hot .  Place the towel over the bubble and move the iron around over the bubble, apply pressure to the iron.  Don't let the towel scorch as this means you have the iron too hot and may burn the wood. It may take a few attempts but by "steaming" the wood you relax the fibers and should bring the bubble down.  When you have the bubble flat you should place a heavy weight on the spot to hold it in place.  The glue under the veneer will soften up with the heat and the weight will hold the wood in place while the glue resets.  Hope this helps.