Google Chrome before 10.0.648.127 does not prevent (1) navigation and (2) close operations on the top location of a sandboxed frame, which has unspecified impact and remote attack vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14349
https://exchange.xforce.ibmcloud.com/vulnerabilities/65948
http://www.vupen.com/english/advisories/2011/0628
http://www.securityfocus.com/bid/46785
http://googlechromereleases.blogspot.com/2011/03/chrome-stable-release.html