On March 23rd, USR, a stablecoin under Resolv, suffered a major security incident. Attackers exploited a private key leak to mint approximately 80 million dollars in unbacked tokens, causing USR's price to collapse to $0.27, a decline exceeding 70%. Resolv has suspended smart contracts and destroyed 9 million anomalous tokens, with 71 million unbacked USR still in circulation. This incident reflects the vulnerability of stablecoins in terms of security and transparency, presenting challenges to market confidence.