When you compare the number of people actually using each of those languages (and therefore the need to actually find and fix security holes) that actually makes PHP the most secure of those three languages s there was far more than ten times the incentive to find security holes in PHP.
Windows always has far more security holes found and fixed each year than any of the alternative operating systems which is why Windows is many times as secure as ANY of their competitors.
All software has security holes - the more that are found and fixed the more secure that software is.