GET's are all removed (by default), but for uri segments you'll just get some character filters, and some anti-xss attempts (assuming you have that on). Nothing anywhere near sufficient to prevent sql injection. Again, didn't dig too deep, but I don't see any validation that would prevent me from doing some level of at least blindsql..
Kind of, anything in permited_uri_chars is allowed. This includes spaces, slashes, commas, %, and a handful of others by default. As I said only skimmed quickly so maybe I'm missing it. Will take a deeper look in a bit once not on mobile.
