{"schema_version":1,"source":"Yieldo","canonical_url":"https://yieldo.me/security#security-cases","name":"Yieldo Verified Crypto Incident Case Studies","unit":"USD","updated_at":"2026-10-20","count":1,"filters":{"year":"2021"},"cases":[{"id":"yieldo:security:poly-network-2021","slug":"poly-network-2021","name":"Poly Network","url":"https://yieldo.me/security/poly-network-2021","occurred_on":"2021-08-10","amount_usd":610000000,"amount_is_approximate":true,"valuation_basis":"More than $610 million, based on Poly Network’s historical estimate in its incident review.","chains":["Ethereum","BNB Smart Chain","Polygon"],"target":"DeFi protocol","mechanism":"Access control flaw","aliases":["Poly Network bridge exploit"],"outcome":"On 23 August 2021, Poly Network received the remaining wallet key and began restoring users’ control over their assets. Frozen USDT followed a separate release process.","outcomes":[{"type":"control_restored","amount_usd":null,"as_of":"2021-08-23","source_id":"poly-restoration"},{"type":"frozen_usdt_pending_release","amount_usd":33000000,"as_of":"2021-08-23","source_id":"poly-restoration"}],"sources":[{"title":"Honour, Exploit, and Code: How we lost 610M dollar and got it back","url":"https://medium.com/poly-network/honour-exploit-and-code-how-we-lost-610m-dollar-and-got-it-back-c4a7d0606267"},{"title":"Poly Network Commences Full Asset Restoration","url":"https://medium.com/poly-network/poly-network-commences-full-asset-restoration-7f5c548423b9"}],"verified_on":"2026-10-20"}]}