First off, the fact that the dispenser is leaking at all is usually a...
...strong indicator that too much detergent is being used.
HE: (2) Tablespoons Per Wash load
HE 2X: (1) Tablespoon
HE 3X: (1) Teaspoon
Remove the TOP COVER of the washer (two screws at the rear of the top cover/slide top cover rearward about an inch & lift off).
Facing the front of the washer---on the top/left of the TUB---there's an accordion- type bellows hose that connects the DETERGENT DISPENSER BOX to the TUB.
Loosen the clamp at the TUB connection & pull off the hose.
Remove the MUSHROOM VALVE (shaped like an umbrella).
Clean off scum/slime accumulation/re-install MUSHROOM VALVE.
Clean the area of the hose that the valve comes in contact with (soap curd/scum).
Re-attach hose and test washer.
Source: LG WM2233HW Leaking soap drawer