Smart Contracts: Common Vulnerabilities and Real-World Cases

This report surveys common smart contract vulnerability classes (access control, price oracle manipulation, logic errors, input validation failures, reentrancy, unchecked external calls, flash loans, insecure randomness, and denial-of-service), illustrates each with high-profile DeFi incidents (Parity, DAO, Mango Markets, MonoX, Wormhole, Beanstalk, KotET, Roast Football, Grape Protocol), and provides mitigation guidance and a note on HackerOne’s bug-bounty contributions to blockchain security.