I noticed someone sending low-fee transaction to thousands of addresses. Fee rate is so small (1 sat/kbyte) that it won't get confirmed and will stay in mempool. BUT when someone sends tx to your address, your bitcoin core will pick it up as your own transaction. And it will treat it as your own transaction and so it will periodically rebroadcast it (because it stays in unconfirmed state due to low fee rate).
If attacker listens for those rebroadcasts over long enough time window they can connect UTXO owners to IP addresses with high certainty.
My recommendation is to add 'walletbroadcast=0' to your bitcoind config to protect yourself from this attack. It will disable the 'my own transaction periodic rebroadcast' feature.