BNB Smart Chain (BSC) activated its Pasteur hard fork on Tuesday, implementing updates designed to close security gaps in bridge verification and validator authorization while increasing block capacity.
According to a Tuesday announcement from BNB Chain, the upgrade went live on the BSC mainnet to strengthen the network's bridge, staking, and governance security. The upgrade combines three BNB Evolution Proposals (BEPs) without altering the network's 450-millisecond block time.
Key Security Enhancements
The hard fork integrates BEP-682 and BEP-695 to address specific network vulnerabilities:
- BEP-682: Rejects duplicate validator entries during cross-chain light-block verification, preventing validators from being counted more than once in bridge approvals.
- BEP-695: Tightens controls over validator key rotation, slashing, and governance voting by removing authority from old validator keys and blocking restricted addresses from voting.
Optimizing Block Capacity with BEP-675
The third component, BEP-675, introduces a new route for specialist builders to submit blocks to validators. Previously, a builder executed transactions prior to submission, and the validator executed them a second time before signing, leading to repeated work that occasionally left blocks underfilled within the 450-millisecond window.
Under BEP-675, builders can submit already-executed blocks. Validators check the proposal against consensus rules, sign and broadcast it, and then complete full execution verification afterward. Builders retain the option to use the previous execution route.
In internal QANet tests mirroring BSC's distributed validators, the new route increased throughput by approximately 88%, moving from 1,237 to 2,324 transactions per second, while average gas used per block rose from 46.35 million to 84.15 million. BNB Chain noted that these figures stem from a controlled test workload rather than live mainnet measurements.
The Pasteur upgrade follows prior network advancements aimed at reducing block times, including the Maxwell hard fork in June 2025 and the subsequent Fermi upgrade.
