As Doug mentioned in his reply, just disconnect and reconnect the leaking couplers.
Occasionally, a spec of dirt might prevent the couplers from sealing. I haven't had to do this with either of my tractors, but I have to tap the stem of the couplers to reseal them or clear out any dirt on the seats. Not a big deal, but I do suggest if you disconnect them and reconnection doesn't stop the leakage, you try tapping on the ends of the couplers. Use a rag over the males ends to soak up any hydraulic fluid that might spurt out. If you have safety glasses or goggles, you might want to wear them when doing this.