Leaking bolts
JF, It could just be some heavy condensation if there isn't too much water in the bilge. One way to know for sure is to run a hose down the cabin top for a few minutes then check the suspected bolts after a while. Do this when it's not freezing out. If there are leaks then you must remove the bolts after the deck dries and re-bed them with a sealant. Sorry, no easy fix for this but to do the work. This is a good time to refinish the teak while the hand rails are off the boat. When you do re-bed, tighten the screws about 80-90%, clean off the ooze and wait until the next day to fully tighten the screws. This leaves enough material to act as a gasket. If you tighten down completely right away, you'll squeeze out most of the sealant and diminish it's effectiveness as a gasket. I usually drill a little countersink around the screw hole on the deck before I add the sealant. It provides an area that doesn't squeeze out too easily, and when it dries leaves a gasket around the screw and on the deck. Take the time, do it right and you should be happy with the results. Good luck.
