Possibly a 2nd- or 3rd-stage nymph of the Brown Marmorated Stink Bug. However, even though I lightened and sharpened your photo, with the white background and the way all extremities are folded I cannot make out the key identifier of white banding on legs and antennae. So it may be the BMSB or a similar stinkbug species. There should be adults around also with the white banding (if BMSB). Stinkbugs are considered garden pests, especially the BMSB.

I agree with Logician. I'll add that the damage from these pests can be impossible for a novice to detect....until it's too late.