alt Hacker NewsOr you visit a webpage that makes a request to an arbitrary server on an arbitrary port while not running a default-deny application firewall
Or you visit a webpage that makes a request to an arbitrary server on an arbitrary port while not running a default-deny application firewall
I don't believe that opens a port to accept an incoming connection.
Even if it did, a web page making a request can't control the source port for the connection. They still couldn't make a local network service exposed to the Internet.