There's not a fundamental flaw with the USB protocol per se.
It's more about USB being implicitly trusted by the software/OS - in addition to that there's driver bugs to be exploited. Here's a few fun things you can do https://www.youtube.com/watch?v=x-7ezoFju6I
It's more about USB being implicitly trusted by the software/OS - in addition to that there's driver bugs to be exploited. Here's a few fun things you can do https://www.youtube.com/watch?v=x-7ezoFju6I