Major Bridge Hacks

Bridges concentrate enormous value behind validation logic — the highest reward targets in Web3. Losses are not random bad luck; they repeat recognizable patterns: compromised keys, flawed upgrades, forged deposit events, and trusted relayers that attest to lies.

Ronin secured a gaming bridge with nine validators and a five-of-nine threshold. Attackers obtained enough keys to authorize fraudulent withdrawals. Social engineering and poor key hygiene turned a trust assumption into a nine-figure loss.

Nomad's exploit began with an upgrade that initialized a trusted root as zero, letting anyone craft valid-looking messages. Copycat drainers followed within hours. Users rarely read upgrade diffs; attackers always do.