Image Credit: bouncebit.com
BounceBit will permanently shut down its standalone Layer 1 blockchain after an attacker exploited an authorization flaw to move about 286.5 million BB tokens from nine accounts. The tokens were worth roughly $2.8 million around the time of the incident.
The project will reissue BB as a BEP-20 token on BNB Chain rather than restart the affected network. BounceBit said private keys, signatures, wallets, hardware devices and exchange accounts were not compromised.
Authorization Flaw Allowed Unauthorized Transfers
The exploit occurred between August 19 and August 20 across 14 transactions. The attacker used a flaw in a protocol module inherited from the Evmos software stack that allowed another account to be specified as the source of funds without properly verifying its authorization.
BounceBit stopped block production at height 20,702,857 at 02:36 UTC on August 20. Its CeDeFi Strategy, Promo Vaults, Prime and real-world asset products were not affected because they operate on separate infrastructure.
BB Will Be Reissued on BNB Chain
The replacement BB token will use balances recorded at block 20,697,260, immediately before the first unauthorized transfer. The 286,543,148 BB moved during the exploit will not be included in the reissued balances.
Holders are not expected to submit claims or manually migrate their wallets. BounceBit said it is also coordinating with centralized exchanges to correct affected balances and address deposits linked to the attacker.
BounceBit Chooses Migration Over Rebuilding Chain
BounceBit said rebuilding the existing Layer 1 would require substantial work, citing the discontinuation of Evmos in May 2026. Most of BounceBit’s core products and user activity have also increasingly shifted toward BNB Chain. BounceBit said:
“Maintaining a standalone Layer 1 is no longer the most effective way to serve our users.”
The move ends BounceBit Chain as an independent blockchain while keeping the wider project operating through BNB Chain and its other products. The migration will effectively neutralize the unauthorized BB transfers by excluding those balances from the replacement token supply.
