The public triggerAutoBurn() maintenance function in BYToken contract on BSC was abused. The attacker took a Moolah flashloan (~422k WBNB), performed Pancake swaps, then called the unprivileged function. This burned ~67.8 quadrillion BY directly from the BY/WBNB pair and called pair.sync(), rewriting reserves to 1 BY + full WBNB. The extreme skew allowed massive BY sells to drain nearly all WBNB liquidity, netting the attacker ~146.60 BNB ($87,402).