if its leaking from the cocking solenoid, first make sure your lpr just isnt too high, it will vent from there if it is.
if the lpr isnt set too high put several drops of oil right into the asa and dry fire it a lot. it might just need some lube.
if that doesnt work then its most likely the gakset between the solenoid and housing. you can take the solenoid out via the 2 tiny screws on the bottom of the noid'. make sure you unplug it from the grip frame so it can come out.
check the gasket, it could be dry or need replacing if its sat for a long time. put some dow33 based grease like sl33k or dye lube or whatever brand you prefer on it. make sure its in place properly when you put it back in. if lubing it doesnt work, it probably needs replacing.
place to buy the gasket:
its a pretty simple job since on the karni you can take the solenoid right out from the bottom without having to undo any hoses or take the cover off the gun. so you dont have to worry about any wrench marks or damaging anything.