This package contains example vulnerable C programs. The best way to learn exploit coding is by doing it. Start your search with the index.html. There are examples of buffer overflows (stack and heap) and format string vulnerabilities. All examples are exploitable with a standard linux/x86 environment.
You can download it from the following link: https://packetstormsecurity.com/files/download/34360/challenges.tgz
Source: https://packetstormsecurity.com/files/34360/challenges.tgz.html