Pull the corner drawer out of the corner unit and place it on a work surface. Be careful when you pull the drawer out to avoid further damage.
Slide a putty knife between the damaged joint to separate the two parts of the drawer, enough to squeeze wood glue into it.
Squeeze wood glue into the damaged joint while you separate the parts with a putty knife. Remove the knife from the joint once you have applied the wood glue. Press the joint together with your hands.
Clamp the joint together with a bar clamp. Wipe off the excess glue with a damp rag and allow the glue to dry for 24 hours. Remove the bar clamp.
Center a small L-bracket on the inside corner of the glued joint. Drive the screw that were included with the bracket through the mounting holes into the glued drawer parts with a screw gun.