BNB Smart Chain activated the Pasteur hard fork on its mainnet at 02:30 UTC on August 25, 2026. The network confirmed the upgrade is live, delivering three coordinated protocol changes that close gaps in cross-chain verification and validator controls while introducing a more efficient route for packing transactions into blocks.

Pasteur groups BEP-682, BEP-695 and BEP-675 under the BEP-673 framework. It leaves the network’s 450-millisecond block time and 100-million gas limit unchanged. The changes had run on the Chapel testnet since July 21 before reaching mainnet. Regular users and most application developers face no requirement to move funds or update client software.

Bridge Verification Tightened Against Duplicate Validators

BEP-682 revises how BNB Smart Chain validates light blocks used for cross-chain transfers. The network already required a supermajority of validator signatures before accepting information from another chain. Previously, the verification process did not reject duplicate entries in a submitted validator set. A crafted list could therefore list the same validator more than once and inflate its voting power.

Under the new rules, duplicate validator entries are rejected before the threshold calculation. Each approval must now come from a distinct validator. BNB Chain presented the change as a preventive hardening rather than a response to any reported exploit or loss of funds.

Validator Key Rotation and Governance Controls Reinforced

BEP-695 addresses several related weaknesses in staking and governance system contracts. When a validator rotates its consensus key, the previous key now loses its administrative authority. Pending slash or eviction processes remain attached to the validator and follow it to the new key, preventing operators from shedding outstanding penalties by changing keys.

The proposal also closes a pathway that allowed restricted or blacklisted addresses to influence governance through signature-based voting. The contracts now check the original signer; if that address is restricted, the vote is discarded regardless of which account submits it.

These adjustments operate at the protocol and system-contract level. Developers of existing applications are not required to migrate contracts.

New Optional Route for Pre-Executed Blocks

BEP-675 introduces an optional block-building path designed to reduce duplicated work inside the short production window. Under the earlier process, a builder executed transactions and submitted a proposed block; the validator then re-executed the same transactions before signing. That repetition consumed part of the 450-millisecond interval and could leave blocks underfilled during periods of high demand.

The new route lets specialist builders submit blocks they have already executed. Validators verify the proposal against consensus rules, sign and broadcast it, then perform full execution verification outside the critical path. Builders may continue using the legacy route if preferred. Adoption of the new path requires operating a full node and enabling the feature through the remote procedure call interface.

Controlled Tests Show Higher Throughput Potential

Internal benchmarks on QANet, an environment built to approximate the geographic distribution of mainnet validators, measured clear capacity gains with the new route. Throughput rose from 1,237 to 2,324 transactions per second, an increase of roughly 88 percent. Average gas used per block climbed from 46.35 million to 84.15 million while the block interval and gas limit stayed constant. Critical-path processing time fell from 125 milliseconds to 15 milliseconds in the same tests.

BNB Chain stressed that the figures were generated under controlled conditions and do not constitute mainnet measurements. Whether comparable gains appear under live traffic will depend on builder adoption of BEP-675 and the mix of real transaction demand.

Node Operator Requirements and Broader Context

All mainnet node operators were required to install client version 1.7.7 before activation and to remove the deprecated EnableBAL setting from their configuration files. Leaving the field in place prevents the updated client from starting. Certain other configuration options and command-line flags are now obsolete or silently ignored.

Pasteur follows earlier upgrades that prioritized shorter block times. The Maxwell hard fork reduced average block time from 1.5 seconds to approximately 0.8 seconds in June 2025; the subsequent Fermi upgrade brought the interval down to the current 450 milliseconds. With block production already accelerated, Pasteur shifts focus toward fuller utilization of existing capacity and tighter security boundaries around bridges, staking and governance.

Operators and developers will now monitor live block utilization, transaction throughput, missed-block rates and validator performance to determine how fully the controlled-test gains translate under sustained mainnet conditions.