BUG CLASSES — DeFi Smart Contract Vulnerabilities

10 bug classes. Each one with root cause, vulnerable code, fix, grep patterns, and real paid examples.

1. ACCOUNTING STATE DESYNCHRONIZATION

#1 Critical bug class — 28% of all Criticals on Immunefi. Real protocols: Yeet, Alchemix V3, Folks Finance, ResupplyFi, MetaPool

What It Is

Two state variables are supposed to stay in sync. One code path updates variable A but forgets variable B. Later code reads both and makes decisions based on the stale B.

Real Value = A - B
If A is updated but B isn't → Real Value appears larger than it is → phantom value