TLDR
- BounceBit will permanently retire its standalone Layer 1 blockchain following a $3 million token exploit.
- An authorization flaw allowed an attacker to transfer 286.5 million BB tokens from nine accounts.
- BounceBit will reissue BB as a BEP-20 token on BNB Chain using pre-attack balances.
- The attacker’s 286.5 million BB tokens will be excluded from BounceBit’s new token issuance process.
- Legitimate BB holders will receive replacement tokens automatically without using external migration or claim websites.
BounceBit will permanently shut down its standalone Layer 1 blockchain and move its BB token to BNB Chain after an authorization flaw allowed an attacker to transfer about $3 million in tokens.
BounceBit Exploit Moves 286.5 Million BB Tokens
The security incident occurred between August 19 and 20, when an attacker executed 14 unauthorized transactions involving nine BounceBit mainnet accounts. Around 286.5 million BB tokens were transferred before the team stopped block production about 40 minutes later.
BounceBit halted the network at block 20,702,857 to prevent further unauthorized transfers. The platform said the incident did not involve stolen private keys, forged signatures or compromised wallets, hardware devices or exchange accounts.
YZi Labs-backed BounceBit to permanently shut down its L1 after 286.5M BB exploit
BounceBit said an attacker exploited a protocol-level authorization flaw in its Evmos-based chain, moving approximately 286.5 million BB from nine mainnet accounts without authorization. The… pic.twitter.com/gMWgITsu4P
— Wu Blockchain (@WuBlockchain) August 21, 2026
The vulnerability came from an authorization flaw in a native module of the Evmos technology stack used to build BounceBit’s Layer 1. The flaw allowed a smart contract caller to identify another account as the source of funds without verifying that the account had authorized the transaction.
BounceBit said its CeDeFi Strategy, Promo Vaults, Prime and real-world asset products were not affected because they operate on separate infrastructure. The company also contacted centralized exchanges to freeze deposits connected to addresses associated with the attacker.
BounceBit Chooses BNB Chain Over Layer 1 Rebuild
Rather than patching the vulnerability and restarting its existing blockchain, BounceBit plans to permanently retire the Layer 1 network. The company said rebuilding the chain would be difficult because Evmos, the underlying technology behind its network, was discontinued in May 2026.
“Maintaining a standalone Layer 1 is no longer the most effective way to serve our users,” BounceBit said.
The company will instead reissue BB as a BEP-20 token on BNB Chain, where many of its products and users already operate. The transition removes the need to rebuild and maintain the existing Evmos-based blockchain following the exploit.
BounceBit launched in early 2024 as a Bitcoin restaking platform and raised $6 million in seed financing co-led by Blockchain Capital and Breyer Capital. The project later expanded its services into CeDeFi yield strategies and tokenized real-world assets.
BB Holders to Receive Reissued Tokens Automatically
BounceBit will calculate balances for the new BB token using a snapshot taken at block 20,697,260, immediately before the first unauthorized transaction. The process is designed to restore legitimate balances while removing the transfers caused by the exploit.
The 286,543,148 BB held by the attacker will be excluded from the new token issuance. Legitimate BB balances, including tokens held in locked staking contracts, will be allocated automatically to corresponding addresses on BNB Chain.
Users will not need to visit a website or manually claim replacement tokens. BounceBit warned holders about potential scams and said there are no external claim links associated with the migration.
The company is also working with centralized exchanges to update customer balances and prevent users from taking losses related to the unauthorized transfers. The timing for restored BB deposits and withdrawals will depend on each exchange as the migration to BNB Chain proceeds.
