Mozilla has issued an update to its Firefox browser today, version 3.0.9, fixing a vulnerability rated as critical in addition to eight moderate or less severe flaws. The one critical flaw involves a memory corruption problem that could be exploited to run arbitrary code, while the two other high-risk flaws involve same-origin violations.

Firefox 3.0.9 also addresses a number of stability issues, including a problem where a corrupt local database caused the browser to "lose" its stored cookies. All changes are detailed in Mozilla's release notes here. The update comes as Mozilla prepares to release the fourth beta of Firefox 3.5 sometime later this week, which should bring significant improvements to JavaScript rendering speeds along other new features.