How many vulnerabilities does Windows have?

Answer 1

Windows regularly receives security updates because new vulnerabilities are discovered often. Each year, hundreds of flaws are reported, ranging from minor bugs to serious threats like privilege escalation or remote code execution. These are tracked in databases like CVE (Common Vulnerabilities and Exposures) and patched by Microsoft through monthly updates. The exact number changes as new versions release and old ones are retired.

Answer 2

One can never know how many vulnerabilities a piece of software has. One can only know how many have been found, and how many have been fixed. Different versions of Windows have different numbers of known vulnerabilities. According to Secunia, Windows XP Home Edition has 361 known vulnerabilities, of which about 40 are unpatched. Windows Vista has 213 known vulnerabilities, of which 11 are unpatched. Windows 7 has 57 known vulnerabilities, of which 5 are unpatched.