Radiant Capital Suffers $4.5 Million ETH Theft in Security Breach

The cross-chain lending protocol Radiant Capital suffered a significant security breach when an attacker exploited a vulnerability and extracted 1,900 ETH, equivalent to approximately $4.5 million. The incident took place almost immediately—within six seconds—after the activation of a new USDC market on Arbitrum, a Layer 2 scaling solution. The attack leveraged a known rounding issue in the codebase used by similar protocols like Compound and Aave. In response, the Radiant DAO Council has temporarily halted its lending and borrowing operations on the platform to prevent further risk to users' funds and to carry out a full investigation.

As Radiant Capital navigates through the aftermath of the hack, no current funds are reported to be at risk, and the company has stated that operations will resume once the investigation is complete. The exploit was pinpointed to a specific address, which was identified through transactions on the Arbitrum network. The broader DeFi community is observing the situation closely, as it underscores the ongoing challenges and risks associated with securing decentralized finance protocols. Security firms have proposed simple preventative measures for such vulnerabilities, including adjusting the collateral factor (CF) when adding new markets.