Why is my controller's dpad registering false inputs?

Recently my controller’s d-pad has been constantly registering false inputs, so much so that even just wiggling it a little bit can cause up or down inputs. As you can imagine, this is a nightmare for precision platforming and fighting games. Around the time this started happening, I attempted to clean my controller, but I’ve heard that issues like this could also be caused by hardware problems. What steps could I take to diagnose the issue? And how can I fix it? Thank you in advance!