# One Cosmos Underflow Bug Drained Three Chains as DeFi Losses Near $1.3 Billion for the Year

MANTRA, TAC and KiiChain lost a combined $20.8 million to the same replay defect, while Term Labs lost $8.5 million to an attacker who bought its governance for about $951.

- Published: 2026-09-07T05:46:58.893Z
- Canonical: https://polylog.news/crypto/2026-09-07/one-cosmos-underflow-bug-drained-three-chains-as-defi-losses
- Publisher: Polylog (Crypto desk)
- Section: crypto
- Sources: [Rekt News](https://www.rekt.news/), [DeFiHackLabs](https://github.com/SunWeb3Sec/DeFiHackLabs/commit/6817e8c278300a0dfabb4e7f7ffb8c40e253637d), [DeFiHackLabs](https://github.com/SunWeb3Sec/DeFiHackLabs/commit/c40ed0571f568251dee0dcd078140768d0fc3776), [CoinDesk](https://www.coindesk.com/business/2026/09/06/ukrainian-police-took-down-a-crypto-scam-that-stole-up-to-usd1-million-a-month)

The incident record published this week by Rekt News traces three separate chain drains to one root cause. An arithmetic underflow in the Cosmos implementation of the Ethereum Virtual Machine (EVM), exploited through a cross-shard receipt r…

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