The 2026 DeFi Pre-Launch Security Checklist: 7 Attack Surfaces Your Audit Probably Missed

The OWASP Smart Contract Top 10 reshuffled in 2026 — reentrancy dropped from #2 to #8, proxy vulnerabilities entered the chart, and business logic flaws climbed. But the real story isn't what moved on the list. It's the gaps between the categories where protocols are still getting drained. After reviewing dozens of post-mortems from Q1 2026 alone (SIR.trading's $355K transient storage exploit, the GMX V1 reentrancy, multiple account abstraction griefing incidents), I've compiled a pre-launch security checklist that goes beyond "did you run Slither and hire an auditor." This is the checklist I wish every protocol team would tape to their wall before deploying to mainnet. 1. Transient Storage (EIP-1153): The 100-Gas Reentrancy You Didn't Plan For The assumption that died: For nearly a decade, developers relied on the 2,300 gas stipend from transfer() and send() being insufficient for state-modifying SSTORE (5,000+ gas). EIP-1153 changed everything — TSTORE costs just 100 gas, well within