Wanchain's Cardano cross-chain bridge attacked, 515 million NIGHT stolen

BlockSec monitoring shows that Wanchain’s Cardano cross-chain bridge was attacked, resulting in the theft of 515 million NIGHT tokens from the cross-chain bridge treasury. Investigations revealed an issue with non-injective signature message encoding in the TreasuryCheck verifier, which allowed different combinations of field values to produce identical byte strings, enabling reuse of the hash and valid signature. BlockSec verified this vulnerability by decompiling the on-chain Plutus V2 bytecode and decoding the redemption data of the attack transactions.