I have a silicon and glass cake mould with the round base made of glass with some silicone feet and a detachable rim made of silicone. One of the feet came lose and dropped off.
What glue I can use to re-attach it?
A high heat silicone adhesive will do the trick. Something like this (obviously only need to buy one, not a whole case).
Also, I've had some luck with oven door adhesive (though never tried on cookware) and auto adhesive.
All are oven safe up to 400-500F continuous, so you should be good for baking.