If you have keep an eye to the latest technology news, thanks to a group called 'Hacking Team', who are an organization hired by governments to spy their citizens, a lot of security exploits have been revealed, one of them is about Flash.
The past week, we have been told about a vulnerability present in Internet Explorer, Chrome, Firefox and Safari which allows to execute malicious code in the victim's computer, and today 3 Flash vulnerabilities were published.
Why you don't need Flash
It has been years since iOS and Android don't offer support for Flash, and nobody cares about it. This legendary plugin doesn't have a good fame, mainly because it always has had many failures in all the possible aspects, and since some years ago it has been less used because new technologies have arrived. Having Flash installed actually is just adding another security hole in your system.
Many popular sites doesn't need Flash actually because they have moved on, Twitter, Facebook and YouTube are some examples (YouTube updated their player to HTML5 not long ago)
If you know Spanish or want to translate it you can read about the vulnerability here: http://hipertextual.com/2015/07/flash-hacking-team
Firefox blocks Flash 13/07/15