Adobe Flash Player is a proprietary browser plugin software that has been found to be riddled with security holes. Currently, for example, there are at least two unpatched "zero-day" vulnerabilities in Flash Player that can be exploited by attackers to remotely seize control over computers running Flash under Windows, Mac or Linux operating systems.
These vulnerabilities are quickly being adopted by cybercriminals who would use them to break into vulnerable systems en masse and install malicious software. Unfortunately, far too many government sites -- including the White House -- require Flash for viewing certain content.
HTML5, on the other hand, is an open technology standard that does not require the installation of buggy, third-party proprietary browser plugins