vsftpd 2.0.8 is often confused in write-ups with the 2.3.4 backdoor incident (CVE-2011-2523). The widely discussed, exploitable backdoor affected vsftpd 2.3.4 (2011) — an attacker-triggered backdoor added to distributed source binaries — not a canonical vulnerability in upstream code for 2.0.8. Many GitHub repos and blog posts focus on the 2.3.4 backdoor and provide exploit wrappers (Metasploit module exploit/unix/ftp/vsftpd_234_backdoor, Nmap NSE script ftp-vsftpd-backdoor.nse).
If you are looking for vsftpd exploits on GitHub, you are likely looking for the famous CVE-2011-2523 vsftpd 2.0.8 exploit github