Cross-chain bridge Gravity Bridge is suspected to have been hacked, resulting in the theft of approximately $5.4 million in assets. According to on-chain analyst Specter, the breach may have occurred due to a leaked contract key. The stolen assets include around $4.3 million in USDC, 274 WETH valued at approximately $553,000, $434,000 in USDT, and $64,000 in PAYG. As of now, Gravity Bridge has not issued an official response to the incident.