Google Chrome before 4.0.249.89, when a SOCKS 5 proxy server is configured, sends DNS queries directly, which allows remote DNS servers to obtain potentially sensitive information about the identity of a client user via request logging, as demonstrated by a proxy server that was configured for the purpose of anonymity.
code.google.com/p/chromium/issues/detail?id=29914
googlechromereleases.blogspot.com/2010/02/stable-channel-update.html
secunia.com/advisories/38545
securitytracker.com/id?1023583
sites.google.com/a/chromium.org/dev/Home/chromium-security/chromium-security-bugs
www.securityfocus.com/bid/38177
www.vupen.com/english/advisories/2010/0361
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A13926