Upbit Warns, Bithumb Suspends SAND After 500M+ Token Mint Exploit on Base

South Korea’s two largest crypto exchanges moved first. On August 22, 2026, Upbit issued a trading caution, and Bithumb suspended SAND deposits and withdrawals after on-chain alerts flagged a suspected exploit. The said exploit happened on The Sandbox’s Base network deployment. Minutes later, blockchain security firm PeckShield confirmed the scale of the breach. According to