title_body: Leak in base of Moka pot
upvoted_answer: Unfortunately I can give you only a half-answer.
  
  A) No, I can’t explain what caused the hole. It looks somewhat corroded and I wonder where the discoloration comes from - maybe worth checking the cause of that and the composition of your water? 
  
  B) I discourage repairing the hole in general. For two reasons:
  
  
  You’re operating the pot under pressure. Any repairs have to hold up to that and not just “hold the water in”.
  Soldering and food safety are a tricky pair. You have to ensure that nothing can leach into the water that shouldn’t be there.
  
  
  In short, you will need either experience beyond some household tinkering (which I kind of suspect you don’t have, because then you’d probably have patched it up already instead of asking here) or have to pay a professional - which considering the price of a new pot probably isn’t economical. (If this pot has a special emotional meaning, other considerations come into play, of course.)
  
  But whatever you do, I encourage you to do some more digging into probable causes before you end up with another hole in the new pot.