Apple led the way in 2015, with a total of 384 vulnerabilities for Mac OS X, closely followed by iOS with 375. Adobe held the next four spots, with three going to AIR (with AIR, the AIR SDK and AIR SDK and compiler) at 246 each, followed by Internet Explorer at 231. Google Chrome was next with 187 vulnerabilities, followed by Firefox at 178, which just shows that despite decades on the market, browsers are still a mess.
The highest-ranking Microsoft operating system was, in fact, Windows Server 2012 at 155 vulnerabilities. Windows 7, 8 and 8.1 had 147, 146 and 151, respectively. After that it was a mix of Acrobat, Linux and other products.