Discover vulnerabilities
Ports
The Ports Database is a comprehensive, searchable database of official and unofficial tcp/udp port assignments, known vulnerabilities, trojans, applications use and more.
Vulnerability databases
Security researchers store & share PoC’s (Proof of Concept) on GitHub.
SearchSploit is a tool that is included with Kali Linux that can be used for searching Exploit-DB (like an offline copy of Exploit-DB).