Dango — Insurance Fund Logic Flaw / Negative Donation (White-Hat Recovery)

Timeline: On April 13, 2026, a white hat exploited a critical logic flaw in Dango insurance fund mechanism on its Cosmos AppChain. The vulnerability was in the replenish_insurance_fund() function which used is_non_zero() instead of is_positive(), allowing a negative donation that drained the insurance fund. Bridge rate limits prevented full extraction of approximately $1.5 million in drained assets, with only $410,010 successfully bridged to Ethereum. The attacker subsequently returned all extracted funds. No permanent loss occurred.