The URLMON.dll is not being so nice in Internet Explorer 7. It can do multiple things to the user, one of them is the browser can crash. This is not the biggest issue though, the DLL can allow a hacker access to your computer when it is given the URL file:// with about 344 dashes after it. Only took a day to find the vulnerability, unless it was someone using the leaked version (then they would have over a week).
News Source: Real Tech News