The company also upgraded the stable version of the browser to version 15, which sports a revamped New Tab page.

on Sept. 16, just over five weeks ago. Google produces an update to its "stable" channel about every six weeks, a practice that rival Mozilla copied with the debut of Firefox 5 last June.

Eleven of the 18 vulnerabilities were rated "high," the second-most-serious ranking in Google's scoring system, while three were tagged "medium" and another four were marked "low."

Google paid $26,511 in bounties, a record, to four researchers, including $13,674 to Sergey Glazunov and $10,337 to "miaubiz," a pair of regular Chrome vulnerability finders who together have accounted for 57% of all bug payments this year. Google has laid out over $170,000 in bounties so far during 2011.

The previous bounty record, set more than two months ago, was $17,000.