A loose cabinet pull can enlarge the hole in a door and eventually crack the finish. Tightening it is simple when the screws are sound, but a stripped hole or missing backer requires a small repair before the handle is put back under load.
Support the hardware
Open the cabinet and hold the pull from the front while loosening the nuts or screws from behind. Keep a small cup nearby for washers and spacers. Inspect the handle for a cracked mounting post before assuming the fastener is the problem.
Retighten carefully
Align the pull squarely with the door and tighten each fastener a little at a time. Stop when the pull is firm; overtightening can crush a hollow door or leave a ring in the finish. Use the correct screwdriver or small wrench so the head is not damaged.
Repair a failed hole
If a screw spins without gripping, remove it and inspect the material. A suitable cabinet-repair plug, longer fastener with a proper backer, or manufacturer-approved insert may be needed. Do not fill a structural problem with soft filler and expect it to hold a frequently used handle.
Test the result
Pull the handle gently in several directions and look for movement at the base. Wipe away fingerprints and save the hardware details for a future replacement. If several pulls are loosening, check whether the door material is swelling or the fasteners were installed with the wrong length.