Starting today, I plan on posting a monthly vulnerability scorecard for common server and workstation Operating System (OS) products. Im going to keep these scorecards pretty clean of discussion, but you can review my methodology, sources and assumptions on this page. For server OSes, the product vulnerabilities analyzed will include those applying to Windows Vista, Windows XP SP2, a subset of Red Hat Enterprise Linux 4 WS (rhel4ws) and Mac OS Xv10.”]
Source: https://www.csoonline.com/article/2136925/january-2007—operating-system-vulnerability-scorecard.html