Internet Explorer 6.0 allows web sites to set cookies for country-specific top-level domains, such as .ltd.uk, .plc.uk, and .sch.uk, which could allow remote attackers to perform a session fixation attack and hijack a user's HTTP session.
https://exchange.xforce.ibmcloud.com/vulnerabilities/17415
http://www.securityfocus.com/bid/11186