Google on Monday patched 19 vulnerabilities in Chrome, paying nine researchers $14,000 in bug bounties for reporting the flaws.
As it did last year, Google beefed up the security of its browser a week before the kickoff of Pwn2Own, the annual hacking contest held at the CanSecWest security conference.
The update to Chrome 9.0.597.107 fixed 16 flaws rated "high," the second most severe ranking in Google's threat system, and quashed three "medium" bugs.
None of the vulnerabilities were ranked "critical," the category essentially reserved for bugs that may let an attacker escape Chrome's anti-exploit "sandbox." Google patched two sandbox-escape bugs, both pegged critical, in Chrome this year.
The bugs patched Monday were in several components, including WebGL, the hardware accelerated 3D graphics API that debuted in early February with Chrome 9; SVG (scalable vector graphics) rendering and animation and the browser's address bar.
Nearly a quarter of the vulnerabilities were identified as "stale pointer" bugs, a term used to describe flaws in an application's, in this case Chrome's, memory allocation code.
As is its practice, Google locked its bug tracking database to bar outsiders from viewing the technical details of the just-patched vulnerabilities. The company blocks public access to flaws for weeks or even months to give users time to update.
Google paid out $14,000, the second highest total this year, for the 15 vulnerabilities found and reported by outside security researchers. Nine different researchers received checks, with Martin Barbella taking home $3,000, Sergey Radchenko $2,500 and two others $2,000 each.
Google and Mozilla, which makes Firefox, are the only browser developers to pay bounties directly to bug researchers.
In hindsight, Monday's update should have been expected: In 2010, Google also patched Chrome the week before Pwn2Own. 2011's Pwn2Own begins March 9, when security researchers will vie for fame and cash by trying to take down not just Chrome, but also the current versions of Apple 's Safari 5, Microsoft 's Internet Explorer 8 and Mozilla's Firefox 3.6.
Monday's patches could be particularly important this year, since Google has a special stake in Pwn2Own: It put up the $20,000 prize for hacking Chrome on the first of the contest's three days. After that, if no one breaks the browser, the rules change and Google will fork over just $10,000, with Pwn2Own sponsor HP TippingPoint ponying up the other $10,000.
At least one other browser builder will issue patches before Pwn2Own's first day of competition. Mozilla has scheduled a security update of Firefox 3.6 for later today.
The patched Chrome 9 can be downloaded for Windows, Mac OS X and Linux from Google's website. Users already running the browser will be updated automatically.