A flaw in the Google Chrome web browser that could reveal the identity of web users trying to surf anonymously, has been identified.

The bug sees domain-name queries that should be sent to a third-party proxy being made by a user's local network.

According to an advisory published to the Full-Disclosure mailing list this week, the bug affects those that use Tor - a free service that re-routes web connections through other IP addresses to disguise the user's identity.

"This presents a serious risk for the users of the services such as Tor, as their DNS data and the little anonymity they have with Tor is leaked outside and in the clear," the advisory said.

The advisory blamed the pre-fetching featuring which is enabled by default. However, according to some developers, disabling the feature does not prevent the problem.

Google said the issue only affects a small number of web users but that it was investigating the problem.

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See also: Google Chrome for Mac released