Ostium Suspends Trading After $18M USDC Loss Tied to Oracle Manipulation

Ostium, a decentralized perpetuals exchange offering up to 200x leverage on products such as S&P futures and gold, halted trading after an attacker siphoned roughly $18 million in USDC from its liquidity vault on July 15. The incident stems from manipulation of the protocol's price-feed infrastructure on Arbitrum. The exploit focused on Ostium's PriceUpKeep forwarder, the module used to push oracle updates on-chain. Instead of relaying valid market data, the attacker injected fraudulent, future-dated reports, creating artificial prices. That enabled the attacker to open and close positions at manipulated levels and extract value directly from the USDC liquidity vault, which holds liquidity provider funds and serves as the counterparty to trades. Blockchain security firm Blockaid confirmed the incident shortly after it was detected. Blockaid said the attacker quickly swapped part of the stolen USDC into ETH via Kyber Network and then spread the proceeds across multiple wallets. The breach hits a protocol that had raised $27.8 million in total funding, including a $24 million Series A round in December 2025 led by General Catalyst and Jump Crypto. Ostium has reported more than $50 billion in cumulative trading volume and has partnered with Nasdaq for equity perpetuals data, positioning itself as a link between traditional markets and DeFi. All positions on the platform settle in USDC. The incident adds to a broader pattern of DeFi exploits tied to oracle and keeper mechanisms. Summer.fi suffered a $6 million loss the previous week in a similar attack. For Ostium, attention is now on whether liquidity providers will be reimbursed. While the project's $27.8 million in funding offers some cushion, an $18 million hit would consume a large portion of its runway. The team has not announced a compensation plan.