Study the break. Replay the proof.
Three real Ethereum incidents, reduced to the bug shape. Read the path, then run the corresponding target in the free local playground.
Poly Network
cross-chain access control failure
A privileged cross-chain message path let an attacker replace the keeper and call protected functionality.
Hundred Finance
first-depositor share inflation
A tiny first deposit and a direct donation distorted the share price until later deposits rounded down to dust.
The DAO
recursive withdrawal before state update
A callback re-entered the split path before the first withdrawal updated its balance, repeating the transfer in one transaction.
Read. Build. Prove.
Read the incident
See the historical failure mode and the path an attacker used.
Build the calls
Translate the pattern into the target’s public entry points.
Prove the flip
Run fresh in Playground and watch the invariant verdict.