Google Chrome before 5.0.375.99 does not properly isolate sandboxed IFRAME elements, which has unspecified impact and remote attack vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11981
http://googlechromereleases.blogspot.com/2010/07/stable-channel-update.html