If a product is Common Criteria certified, it doesn't necessarily mean it is completely secure, for example Microsoft Windows 2000 is a certified product of EAL4 +, but regular security patches for security vulnerabilities are still published by Microsoft for Windows 2000.
It doesn't necessarily mean. It is completely secure. Example Microsoft Windows 2000 is a certified product of EAL4 +. A product is Common Criteria. This Common Criteria is certified. Regular security patches for security vulnerabilities are still published by Microsoft for Windows 2000.