I don't think 10.8 has the vulnerability. At least my MBP with 10.8 doesn't appear to have it. Both of the test URLs from HN had the desired behavior in Safari

I don't think 10.8 has the vulnerability. At least my MBP with 10.8 doesn't appear to have it. Both of the test URLs from HN had the desired behavior in Safari on that machine (ie they blocked content / didn't establish a connection). EDIT: I'm not using Little Snitch or anything other than the builtin OSX firewall.