Microsoft Internet Explorer 7 allows remote attackers to cause a denial of service (application crash) via Javascript that calls the alert function with a URL-encoded string of a large number of invalid characters.
https://exchange.xforce.ibmcloud.com/vulnerabilities/45639
http://www.securityfocus.com/archive/1/496926/100/0/threaded
http://www.securityfocus.com/archive/1/496830/100/0/threaded
http://www.openwall.com/lists/oss-security/2008/10/03/8