United States Computer Emergency Readiness Team
US-CERT offers mailing lists and feeds for a variety of products including the National Cyber Awareness System and Current Activity updates. The National Cyber Awareness System was created to ensure that you have access to timely information about security topics and threats.
Timely information about current security issues, vulnerabilities, and exploits
Weekly summaries of new vulnerabilities. Patch information is provided when available
Advice about common security issues for the general public
Up-to-date information about high-impact types of security activity affecting the community at large