Question about traceability from vulnerability reports to source code

Hi, Thanks for the great product. As a part of my research, I'm trying to find the files that have been changed to fix vulnerabilities. I tried to search CVE ids from svn log, but was able to find only three CVEs out of over 100 CVEs that were reported in NVD (National Vulnerability Database). Is it possible to trace files that have been changed to fix vulnerabilities? Can anyone let me know which data sources I might need to check? If this is not the right place to ask this question, would you please let me know where I can ask? Thanks for your help! Yonghee