The YZi Labs-backed project BounceBit is permanently shutting down its standalone Layer 1 blockchain following an exploit that allowed an attacker to move 286.5 million BB tokens, valued at over $3.1 million. Rather than attempting to rebuild the network, the project will reissue BB tokens on BNB Chain, ending BounceBit’s independent chain after more than two years.
According to an announcement on X by BounceBit Chain, block production was stopped at block height 20,702,857 after the attack uncovered a vulnerability in the network's underlying Evmos-based system. The flaw enabled an attacker to designate another account as the source of funds without obtaining authorization, resulting in the unauthorized transfer of approximately 286,543,148 BB from nine mainnet accounts.
The BounceBit team stated that no private keys were compromised, no signatures were forged, and user wallets or exchange accounts were not hacked. The vulnerability existed entirely within the blockchain's software. Although the project initially considered repairing the network, it ultimately decided that rebuilding would require excessive effort because the Evmos codebase utilized by BounceBit has been discontinued.
Instead of upgrading or rebuilding the Layer 1 network, BounceBit is issuing BB as a BEP-20 token on BNB Chain. New balances will be determined using a snapshot taken at block 20,697,260, which occurred prior to the first unauthorized transfer. The 286.5 million BB tokens moved during the exploit will be excluded from the new token supply.
BounceBit noted that users will not need to manually apply for the new tokens, as the project intends to automatically credit the corresponding BNB Chain addresses. Staked and unbonding BB balances will likewise be processed based on the pre-attack snapshot.
The shutdown is limited to the Layer 1 blockchain and does not affect the broader BounceBit business. The team explained that most of its products already operate around BNB Chain, where user activity is concentrated. Transitioning away from its own Layer 1 enables the project to allocate more resources toward existing products, including its CeDeFi, Prime, and RWA offerings, which the team confirmed were unaffected by the exploit and will continue operating normally.
As exchanges coordinate support for the new BB token, BounceBit has cautioned users to steer clear of unofficial migration links and fake contracts.
