On February 3, 2023, an attacker exploited a bug in the SperaxUSD token contract by pre-computing a Gnosis Safe address and sending 11 USDs to it. When the Safe was created, this triggered an overflow in the balance calculation, allowing the attacker to mint 9.7 billion unbacked USDs and exchange approximately $250K worth before the contract was paused.

SperaxUSD, the Arbitrum ecological stablecoin protocol, tweeted that an attacker increased the token balance of his address to 9.7 billion without providing the corresponding collateral, and before the Sperax team and Arbitrum ecosystem partners jointly stopped, Approximately $300,000 was liquidated.