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NFT Smart Contract Security Guide
Common vulnerabilities in NFT contracts and how to prevent them, based on our analysis of major NFT exploits.
ExVul Research Team
Security Researchers
August 202410 min
#NFT#ERC721#Security
Introduction
NFT contracts have become high-value targets for attackers. This guide covers the most common vulnerabilities we find in NFT audits and how to prevent them.
Minting Vulnerabilities
- Unrestricted minting allowing unlimited token creation
- Signature replay attacks in whitelist minting
- Front-running of mint transactions
- Integer overflow in mint count tracking
SecureMint.sol
// Secure whitelist minting with signature verificationfunction whitelistMint(uint256 quantity, bytes calldata signature) external payable { require(!usedSignatures[signature], "Signature already used"); require( _verifySignature(msg.sender, quantity, signature), "Invalid signature" ); usedSignatures[signature] = true; _safeMint(msg.sender, quantity);}Always mark signatures as used before minting to prevent replay attacks.
Mint Controls
Proper access control and limits
Signature Security
Prevent replay attacks
Metadata
Secure on-chain or IPFS storage