Microsoft's latest super-soar-away success story, "Internet Explorer 7" was born today. It's less than 24 hours old and it has security advisories posted against it. Given that it's just a superficial hack of their older and even more insecure Internet Explorer 6 it's hardly surprising that they are having security issues already.
If they don't want to spend the money to produce a decent modern standard compliant browser, then they should just give up and tell people to use Firefox or Opera.