Google has patched 13 security flaw in its Chrome web browser, six of which the search engine ranked as 'high' in its threat scoring system.

Google also added support for extensions and bookmark synchronisation to the production version of Chrome for Windows.

Although a beta of Chrome in December 2009 included support for both extensions and bookmark sync, this is the first time that the features have appeared in the 'stable' build channel, a term Google uses in place of 'final'.

Google also touted the growth of its extension gallery, which now has more than 1,500 add-ons, a five-fold increase over the 300 available at its debut last month.

Only Windows' stable edition supports extensions and sync; Linux users must use the beta channel build for the same features, while Mac owners have to drop all the way down into the least reliable version, dubbed the 'developer' build by Google, to access extensions.

According to Ian Fette, a product manager on the Chrome team, the new Windows version also adds several new HTML and JavaScript APIs (application programming interfaces), all of which relate to storing web 2.0 data locally for offline use.

Chrome patches a baker's dozen security vulnerabilities, including six tagged as a 'high' threat.

Details on four of the six serious flaws have been blocked on Chrome's bug tracker to prevent hackers from using the information to create exploits.

"The...bugs may be kept private until a majority of our users are up to date with the fix," explained Anthony Laforge, a Chrome program manager, in a blog.

Google also used the opportunity to brag about Chrome's speed increase since the last stable build for Windows.

"We've improved performance (as measured by Mozilla's Dromaeo DOM Core Tests) by 42 percent over our last stable release and 400 percent since our first stable release last year," claimed Nick Baum, yet another product manager, on the official Chrome blog.

According to PC Advisor's sister title Computerworld, in tests using the SunSpider JavaScript benchmark suite, Chrome is slightly slower than Apple's Safari, but significantly faster than other rivals such as Mozilla's Firefox and Microsoft's Internet Explorer.

Chrome is now the third-most-used browser on the planet, having grabbed the number three spot from Safari last month, according to web measurement company Net Applications.

Google Chrome can be downloaded for Windows XP, Vista and Windows 7 from the company's site.


Broadband speed test

See also: Google wins PC Advisor's Best Web Browser award