Only if your openclaw instance is publicly exposed on the internet... which is not the case for most people
A malicious web page runs JavaScript that makes a fetch() or XMLHttpRequest to http://localhost:CLAWPORT — your browser executes that from your machine, so it bypasses your router/firewall entirely. If OpenClaw is listening on localhost with no auth, the browser just connects to it. Same-origin policy doesn’t save you because the request originates from your own machine.