In order to stay secure, Ubuntu users should simply apply all Ubuntu security updates to their systems when they become available.
For some vulnerabilities that are highlighted by the media, we've provided additional information as part of our KnowledgeBase:
Ubuntu CVE Tracker (web view)
- How to handle backporting security updates
- How to test the update
- Proof of Concept (PoC)
- Build test suites (eg, 'make check')
- ABI compatibility (eg, check-symbols, nm)