Adobe has reported a vulnerability in several of its applications. The flaw, which Adobe rates as “critical,” exists in Flash Player, Adobe Reader and Acrobat 9.x running on most operating systems. It could crash a victim’s PC and let hackers take over the machine. The flaw couldn’t come at a worse time — Apple has been criticizing some Adobe technologies, including Flash, in recent months for several reasons, one of which has been security. Together with Microsoft, Apple pushing HTML5 as an alternative to Flash.