Summer.fi hack concerns rose after CertiK said a suspicious transaction used a $65.4 million flash loan to make about $6 million.
DeFi yield platform Summer.fi said its protocol guardians are pausing all vaults after blockchain security researchers reported that a suspicious transaction used a $65.4 million flash loan to make about $6 million through liquidity manipulation.
Summer.fi confirmed a pause and an investigation, but not the underlying cause. The team said in a Monday post on X, July 6, that it was aware of the reported exploit and was investigating the root cause:
“We are aware of the reported exploit a little earlier today and are investigating the root cause. The protocol guardians are currently pausing all Vaults across the Lazy Summer Protocol.”
CertiK Alert, the threat-monitoring account run by blockchain security firm CertiK, said it had detected a suspicious transaction involving Summer.fi.
As per CertiK’s findings, the hacker managed to gain around $6 million after manipulating liquidity by utilizing a little over $65 million in flash loans in the process.
Summer.fi, previously known as Oasis.app, describes Lazy Summer as a system for accessing DeFi yield through automation and risk curation.
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Summer.fi Hack Context Includes Wormhole Recovery
Before the rebrand, Oasis.app was involved in the 2023 recovery of funds tied to the Wormhole bridge attacker.
The project said at the time that it had worked with whitehat hackers after receiving an order from the High Court of England and Wales, sending recovered assets to a court-authorized third party.
The recovery drew attention due to the way it was conducted. Summer.fi claimed that it was using an unknown until that moment vulnerability associated with admin multisig access. The project also added that such access was used only for protecting the assets of the users, which were never in danger.
However, Summer.fi faced a separate Lazy Summer vault stress incident in the late 2025. Commenting on the incident in the post-mortem, the project stated that Arbitrum USDC▲$0.9999 Vault was hit by that following the Balancer exploit, USDX depeg and Silo oracle reporting incidents.
But at the time Summer.fi argued that the underlying failure came from Silo and was outside the control of the Lazy Summer Protocol and the Summer.fi interface.
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