Adobe Shockwave tops the list of software that most user left outdated on their PCs, followed by VLC Media Player, Skype, Java Runtime Environment, 7-Zip File Manager, and Foxit Reader. Almost 15% of all Windows 7 computers and 9% of Windows 10 computers are running an outdated version of the operating systems. WannaCry was taking advantage of a dangerous security hole in Microsoft Windows that had already been fixed by the company months before the ransomware threat strikes the whole world.
Source: https://thehackernews.com/2019/01/software-vulnerabilities-hacking.html