Food safety
Can dogs eat peach, plum & cherry stones?
No — don't give this
The flesh is fine in small amounts, the stones aren't — a choking and blockage risk, and they contain cyanide compounds.
Being honest about this
Dogs differ, and amount matters — a crumb of something rich is not the same as half a packet. Treats of any kind should stay under a tenth of what your dog eats in a day. If you're unsure, your vet would far rather take the call.