The exploit could allow a malicious user to execute arbitrary code on a remote system and is rated highly critical by Secunia.

“The vulnerability is caused due to an error in the handling of parent windows and can result in a function call using an invalid pointer. This can be exploited to execute arbitrary code when a user e.g. visits a specially crafted web page and closes opened pop-up windows” says the Secunia security advisory.

The vulnerability affects both Mac OS X and Windows versions of the browser. Apple is yet to release an update to close the flaw.

The update takes the browser to 10.52, and is mostly a stability fix for Windows, with many bug fixes. A full list of changes can be found in the changelog.

Opera 10.52 on Mac finally sees the arrival of the Carakan JavaScript engine, Vega graphics library, and Opera Presto 2.5 browser engine.

Early benchmark results also look promising, showing that Opera is on par with or better than Google Chrome 5 (beta) for Mac. Full benchmarks can be seen on the Choose Opera blog.

The Opera browser can be downloaded from the Opera website.

This figure includes 50 million users on Windows, Mac and Linux, plus another 50 million users browsing the web with Opera Mini on their mobile devices.

100 million users comes after a staggering 30% jump in desktop users from the same time last year, mostly attributed to the release of Opera 10.x browsers.

“Our focus on speed, security, innovation and usability continues to yield results. We always listen to the needs and wants of our users, and they reward us by choosing Opera,” said Jon von Tetzchner, Co-founder, Opera Software.

Congratulations to Opera on the achievement, and new users can download Opera for their computer or mobile device from the Opera website.

Chrome 5.0.307.7 brings many new features to Mac, and also included updates for Linux users.

Mac users now have access to these new features:

• Extensions
• Bookmark sync
• Bookmark manager
• Cookie manager
• Task manager

The team have also worked hard to ensure the browser is more stable, while having better support for plug-ins like Adobe Flash Player.

The new updated will be pushed out to existing users, or can be downloaded using the links below:

• Windows: http://www.google.com/chrome/eula.html?extra=betachannel
• Mac: http://www.google.com/chrome?platform=mac
• Linux: http://www.google.com/chrome?platform=linux

Not much has changed so far, but Windows versions will now use the default download folder for downloading files, while the Mac version is now more stable with extensions.

Linux versions now include support for desktop notifications, along with improved support for complex text such as Arabic and Hebrew.

Being development versions, they are prone to instability and crashes. There is currently one known bug in the Mac version, which will crash the browser when a user clears the cookies.

Users can jump on the dev channel version of Google Chrome by following instructions on the Chromium website.

This is new version is in addition to the beta version, which Mac users have been able to test for the last few weeks.

Almost 1,400 extensions are currently available for Chrome users.

Mac users wanting to test out extensions can install the developer build of Google Chrome from the Chromium Developer website, noting that this is a development build and is prone to bugs.

Beta users of Google Chrome Mac will have to wait until current code migrates from the Dev to Beta channel to test out extensions.

Version 4.0.249.30 has been promoted to the Beta channel for Windows, Mac and Linux.

Mac users who had a previous developer  build installed will automatically be moved to the Beta channel.

Chrome on Linux is integrated tightly with native GTX themes, while updates are managed by the standard system package manager.

Mac users will also notice that Chrome has a native Mac OS X graphical user interface.

Download links are below:

• Download Google Chrome Beta for Windows
• Download Google Chrome Beta for Mac
• Download Google Chrome Beta for Linux

“Opera 10 showcases a sleek new design coupled with our new Turbo technology, which keeps Web pages loading lightning fast, even if your connection slows down” says the spiel on Opera’s homepage.

Other new features include an in-line spell check, full Acid3 compliance and mouse gestures.

A full run down on features and download links for Windows, OS X, and Linux can be found on the Opera 10 site.

The builds, which are still only in the dev channel, is now stable on Mac, but is still lacking features with the dev team not recommending the browser for every day use.

“Google Chrome for Mac OS X Developer Release is a very early release version and does not yet have some of the functionality that a full general release version would have. Many of the features still under development affect the privacy behavior of Google Chrome for Mac OS X. The issues marked in bold text below will be resolved prior to releasing Google Chrome for Mac OS X to the beta channel for broader consumer use” says the note from Google.

A download link is available from the Early Access Release Channels on the Chromium website.

“The v8 team did some amazing work this quarter building a working 64-bit port.  After a handful of changes on the Chromium side, I’ve had Chromium Linux building on 64-bit for the last few weeks” said Google Chrome Software Engineer Dean McNamee.

The new builds can be downloaded from here, with build instructions also being available for Linux users.

A Windows and Mac version are set to follow.