Bridge hacks drain $340M from DeFi

TLDR

Recent data shows 14 cross-chain bridge hacks in May stole about $340 million from DeFi, reinforcing that bridges are one of the most dangerous parts of crypto infrastructure.

1. A new report attributes $340.7 million in May losses to 14 bridge exploits, on top of hundreds of millions lost earlier this year.
2. The worst incidents exploit the complexity of cross-chain bridges, often targeting off-chain infrastructure and multisigs rather than just on-chain code.
3. The key things to watch are which teams redesign bridge security, cap bridge TVL, and respond quickly to incidents before stolen funds are laundered.

Deep Dive

1. Scale Of The Recent Bridge Losses

Analytics cited by AMBCrypto report that 14 major bridge exploits in May 2026 stole about $340.7 million from cross-chain protocols, including Verus, THORChain, Gravity Bridge, and IoTeX Bridge, highlighting persistent interoperability risk. The same report notes that after a relatively contained $169 million in Q1, Mays spike brings year-to-date losses from crypto hacks close to $770 million, with April still the worst month so far, at over $600 million in thefts, largely from cross-chain systems. The pattern is that a small number of large bridge incidents dominate total losses, which means bridge design has an outsized impact on DeFi security compared to many single-chain dapps.

2. Why Bridges Keep Getting Hacked

Cross-chain bridges must coordinate messages, validators, and large asset pools across multiple networks, so a single bug or key compromise can unlock very large sums. In the Kelp maker/">DAO bridge exploit, attackers tied to the North Korea-linked TraderTraitor group drained about $292 million via a fake burn event that abused off-chain bridge infrastructure rather than Kelps core smart contracts. Earlier, Radiant Capitals cross-chain lending protocol was effectively killed by a roughly $50 million exploit that compromised multisig signers using malware, and the stolen funds were then laundered through privacy tools such as Tornado Cash. These examples show that even if smart contracts look solid, surrounding infrastructure, signers, and operational security can be the weakest link.

3. What To Watch And How To Think About Risk

For protocols, stronger bridges usually combine decentralized validation, cryptographic verification of messages, independent security audits, and hard caps on how much value a single bridge can hold. Fast, coordinated responses also matter: in the Kelp case, Arbitrums Security Council froze more than 30,000 ETH, creating a significant pool of assets that remained recoverable even after most unfrozen funds were laundered. Institutions are starting to design around bridge risk entirely, for example by using synthetic exposure structures that keep assets in regulated custody while accessing on-chain strategies, which indicates where safer DeFi might be heading.

Conclusion

Bridge hacks draining roughly $340 million in a single month underline that interoperability remains one of DeFis largest unresolved attack surfaces. Until bridge designs and operational security significantly improve, cross-chain yield and convenience come with elevated structural risk that users and protocols need to price into their decisions.