MANTRA Chain Revealed Details of $3.6M Attack

On August 20, 2026, MANTRA Chain experienced a security breach resulting in the unauthorized movement of 720.9 million MANTRA tokens, valued at approximately $3.6 million. The attacker exploited an unsigned-integer underflow vulnerability within the Cosmos EVM module, which allowed for unauthorized withdrawals from economically inactive balances. This incident forced the network to halt operations for over 30 hours to implement a fix via version v8.4.0. While no user funds were drained from active accounts, the attack significantly increased the circulating supply of the token. The vulnerability stemmed from a lack of balance checks during state reconciliation between the EVM and Cosmos Bank modules. Although a patch existed in the development branch since May, it had not been backported to the production release until after the exploit occurred. MANTRA Chain has since initiated recovery procedures with law enforcement and exchanges to address the stolen assets. This event highlights the critical importance of rigorous security auditing and timely patch management for RWA-focused blockchain infrastructures.