CVEDETAILS claims to be the ultimate security vulnerability database providing an easy to use web interface to CVE vulnerability data.
You can browse for vendors, products and versions and view cve entries, vulnerabilities, related to them. You can view statistics about vendors, products and versions of products.
Data is are taken from National Vulnerability Database (NVD) xml feeds provided by National Institue of Standards and Technology and several other sources like exploits from exploit-db.com, vendor statements and additional vendor supplied data and Metasploit modules.