Pasteur hardfork lands August 25 as BSC throughput jumps 88%

Pasteur hardfork activates on BSC mainnet at 02:30 UTC August 25, closing a bridge validator loophole and lifting testnet throughput 88% to 2,324 TPS.

BNB Chain confirmed the date and client requirement in a blog post published August 14, alongside documentation for node operators. All mainnet nodes must run client v1.7.7 before activation or risk falling off the network.

The upgrade bundles three proposals under meta proposal BEP-673. BEP-682 and BEP-695 address security gaps in the bridge and staking contracts, while BEP-675 lets builders hand over pre-executed blocks to validators. The hardfork follows Fermi, which cut BSC block times to 0.45 seconds in January 2026. Pasteur keeps that pace but aims to pack more transactions into each block.

Closing the duplicate-validator loophole

BEP-682 rewrites how BSC verifies cross-chain transfers. When assets move onto the chain, BSC runs a precompile at address 0x67 that counts validator signatures against a known validator set. The transfer only clears once a supermajority signs. But the current process does not prevent the same validator from appearing multiple times in the approval list. A crafted validator set could list the same signer several times, counting that signer's voting power on every appearance and clearing the threshold with fewer genuine signatures than the rules require. BEP-682 removes duplicates before the count, ensuring inflated sets no longer pass.

The proposal addresses a specific weakness in BNB Chain's transfer checks, though the network did not say the issue had been used to steal funds. Cross-chain bridge attacks have caused more than $4 billion in losses since 2021, with stolen validator keys and weak transfer checks among the vulnerabilities exploited in major incidents, according to crypto.news reporting. In July, a Cardano-to-BNB Chain bridge operated by Wanchain reportedly lost about 515 million NIGHT tokens, valued at roughly $9 million at the time.

Retired keys and fuller blocks

BEP-695 addresses a weakness in staking and governance. When validators rotate their consensus keys as routine maintenance, the assumption is that a retired key stops carrying authority. That was not how it behaved. The proposal makes three fixes: a rotated old key loses its validator-admin privileges, a validator can no longer avoid pending eviction by rotating keys, and blacklisted addresses are blocked from signature-based governance votes.

BEP-675 targets block production efficiency. Blocks currently get executed twice on BSC — the builder runs the transactions to confirm validity, then the validator runs them all again before signing. That second execution eats into the 450-millisecond window. BEP-675 allows a builder to hand over a block it has already executed. The validator checks it against consensus rules, signs, broadcasts, and finishes full verification afterward.

Testnet data from QANet showed validator execution time dropped from 125 milliseconds to 15 milliseconds. Throughput rose from 1,237 to 2,324 TPS, an 88% gain, with the 100 million gas limit and 450 ms block interval unchanged. Average block gas used rose from 46.35 million to 84.15 million. BNB Chain cautioned these are controlled-workload figures that still need validation under mainnet traffic, especially when multiple builders bid for the same slot.

Node operators must update to client v1.7.7 before August 25 and remove [Eth] EnableBAL from config.toml or the node will fail to start. Builders who want the BEP-675 path may need to run a full node instead of a fast node since the builder now produces a fully executed block. Legacy bids keep working, just with less packing time.

The hardfork has broader implications for BSC's competitive standing. BNB trades at $606.35, down 0.67% over the past 24 hours, according to Binance data. A successful Pasteur activation could restore user confidence in BSC's bridge infrastructure after years of cross-chain exploits, while the throughput gains position the chain to absorb more DeFi activity without increasing block speed — a key consideration as competing L1s race for transaction volume.

This article is for informational purposes only and does not constitute investment advice.