Inside the GMX Exploit: How a Reentrancy Bug Led to a $42M Loss

Aug 22, 2025 · 9 min read · GMX is one of the leading decentralized perpetual exchanges in DeFi, enabling users to trade leveraged positions directly on-chain across Arbitrum and Avalanche. In July 2025, GMX suffered a critical exploit that drained approximately $42 million fro...