BNB Chain Activates Pasteur Hard Fork on BNB (BNB) Smart Chain at 02:30 UTC

Pasteur Hard Fork Goes Live on BSC Mainnet

BNB Chain, the ecosystem behind the altcoin BNB, activated the Pasteur hard fork on BNB Smart Chain (BSC) mainnet at 02:30 UTC on Aug. 25, 2026. The network said the upgrade strengthens bridge, staking and governance security while giving blocks additional capacity without shortening block times further. The network confirmed the activation in an official announcement, with BSC continuing to produce blocks at its existing 450-millisecond interval and no major disruption publicly reported immediately after the upgrade. BNB Chain had warned node operators to complete the mandatory update before the fork, noting that incompatible clients risked falling out of sync. Pasteur combines BEP-682, BEP-695 and BEP-675 under the broader BEP-673 plan, and the changes had operated on BSC’s Chapel testnet since July 21 before reaching mainnet. The core bridge fix, BEP-682, changes how BSC verifies light blocks submitted through cross-chain infrastructure: duplicate validator entries in a submitted list are now rejected before the network calculates whether the required voting threshold has been reached. Previously, a crafted request could include the same validator more than once, counting those entries separately and risking an approval appearing to have support from more independent validators than it actually did. BNB Chain did not report that attackers had exploited the flaw or attributed any previous asset losses to it, so the change is a preventive correction rather than a response to a disclosed theft. Bridge attacks remain a leading security concern across decentralized networks, with cumulative losses in the billions tied to compromised keys, contract flaws and weak message verification. Under BEP-695, when a validator replaces its operator key, the previous key loses its management rights, and slashing and removal processes remain attached to the validator rather than disappearing when the operator address changes; restricted addresses are also barred from using offchain signatures to participate in governance, with updated contracts checking the original signer before a delegated vote is counted.

The third component, BEP-675, targets block capacity through an optional route for specialist builders. Under BSC’s previous block-building process, a builder executed transactions before submitting a proposed block, and the validator executed them again before signing; BNB Chain said that duplicated work consumed part of the 450-millisecond block window and could leave blocks underfilled during heavy demand. The new route allows builders to submit blocks they have already executed. Validators check the proposed block against consensus rules, sign it and broadcast it, then complete full execution verification afterward. Builders can continue using the previous process, and the new route must be enabled through the network’s remote procedure call interface, giving participants time to integrate it. In tests on QANet, an internal environment designed to mirror BSC’s geographically distributed validators, the route lifted throughput by about 88%, from 1,237 to 2,324 transactions per second. Average gas consumption per block rose from 46.35 million to 84.15 million, while the 100-million gas limit and the 450-millisecond block interval remained unchanged. BNB Chain cautioned that the figures came from a controlled test workload and were not mainnet measurements. Because Pasteur does not raise the 100-million gas limit, any sustained capacity gain depends on builders enabling the route and submitting fuller blocks. Applications building on BSC, including automated market maker platforms, could see fuller blocks during demand spikes if builders adopt the route. Pasteur follows earlier upgrades centered on reducing block times: BSC’s Maxwell hard fork cut average block time from about 1.5 seconds to roughly 0.8 seconds in June 2025, and the Fermi upgrade later brought it to 450 milliseconds. Live data on block utilization, transaction throughput and missed-block rates will show whether the capacity improvement carries over to sustained mainnet demand.

Taken together, Pasteur bundles security hardening with a capacity experiment in a single activation cycle. The official announcement confirms the fork is live, but the release notes stop short of presenting QANet’s 88% improvement as production performance. Node operators were required to install client version 1.7.7 and remove the deprecated EnableBAL field before activation; keeping that field in the configuration would prevent the updated client from starting. For the altcoin ecosystem, the more relevant near-term signal is whether the new builder route produces fuller blocks without raising missed-block rates. Pasteur operates at the protocol layer, a separate risk surface from wallet-level concerns such as blind signing, where users approve messages without full visibility, and its success will be measured by on-chain validator performance rather than by token price reaction.