What happened
On June 4, 2026, BYToken's BY/WBNB liquidity pool on BSC lost about 146.60 WBNB (approximately $88,550) after its public auto-burn path was used to distort the pair's reserves.
Technical root cause
BYToken exposed triggerAutoBurn() without an access-control restriction. When its own balance was empty, the reachable path could burn BY from the AMM pair and call sync(), allowing the pair's reserve ratio to be manipulated.
How it happened
- The attacker obtained temporary BY liquidity from an on-chain flash-loan vault, shaped the BY/WBNB reserves, then called the unrestricted auto-burn path.
- The burn and sync() left the pool with a severely distorted reserve ratio, after which swaps drained its WBNB liquidity.
Protocol details
Classification
Token
Protocol Type
Exploit/Flash Loan Attack
Attacker Address
0x047547A4fa4a67C1032d249B49EC1a79c0460BAD
Exploit Transaction
0xe31c681eee764fb94b…0541980979
Evidence
Proof of concept
1 availableSources
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