As we learned again, most recently with the Equifax data breach, delay in installing security patches and updates for your software as soon as they become available can lead to disastrous consequences.  Adobe has recently issued critical updates to a number of its software programs including the popular, but seriously vulnerable Adobe Flash.
Flaws in Adobe Flash have been exploited by hackers and identity thieves against individuals, companies and government agencies including the U.S. State Department and the White House.  In 2010 Steve Jobs vociferously complained about its security and it has routinely been cited as being extremely vulnerable.   According to security company, Symantec in 2015 80% of the newly discovered software vulnerabilities which can be exploited by malware created by cybercriminals involved Adobe Flash. Adobe has announced that it will be retiring Adobe Flash in 2020.  It will still be issuing security patches until then, but now is a good time to move away from Adobe Flash if you have not already done so.
TIPS
If you are going to continue to use Adobe Flash, it is imperative that you update your software with the latest security patches when they are issued.  Here is a link to the latest updates for Adobe Flash.
https://www.us-cert.gov/ncas/current-activity/2017/11/14/Adobe-Releases-Security-Updates
However, it may well be time for you to replace Adobe Flash to avoid future problems.
Here is a link to a website with alternative plugins you may wish to consider to replace Adobe Flash.
http://alternativeto.net/software/flash-player/