Bitcoin Core 32.0 has entered its final testing phase with a release candidate tagged on September 14, according to the project's release schedule. The software is scheduled for a finished release on October 10, marking the next major update to the Bitcoin node software. The update maintains Bitcoin's consensus rules while introducing significant improvements to transaction processing and wallet functionality. The official GitHub release shows v32.0rc1 at commit d0231bb, signed with a verified maintainer signature on Sept. 14 at 12:58 UTC. Developers entered feature freeze on August 20, limiting work to fixes needed before release, and split the 32.x branch from the main development branch on September 14 to start the release-candidate cycle.
Version 32 introduces a dual fee estimator system that combines current block data with pending transaction information. The new mempool estimator produces both economical and conservative estimates from current pending transaction conditions, checking recent block activity before using it and rejecting estimates when the mempool appears too sparse or unhealthy. When both systems produce valid results, estimatesmartfee returns the lower fee estimate, allowing the new method to lower recommendations when current mempool conditions support it. The software preserves the previous block-history estimator and adds a fee_rate_estimator option letting users request block_policy, mempool_policy or the combined default behavior. Wallet fee calculations will use the combined default estimator, with higher verbosity levels exposing mempool-health statistics for applications that need more detail.
The update enables concurrent processing of multiple threads for fetching transaction data from databases while checking blocks. Bitcoin Core can now prefetch previous transaction outputs (prevouts) from the chainstate database across several worker threads while block validation continues, with the default set to eight prefetch threads and operators able to raise it to 16 or disable parallel fetching. Prevouts identify the coins being spent by transaction inputs, and the improvement is intended to cut time spent waiting for disk reads when nodes process blocks containing inputs not already available in faster memory caches. The effect will vary with storage hardware, cache behavior and node configuration, with operators controlling the setting through -prevoutfetchthreads=<n>.
Developers addressed a critical wallet notification flaw affecting non-Windows systems under specific conditions. An authenticated RPC user with wallet creation permissions could craft a wallet name containing special replacement characters when the node was configured with -walletnotify, causing arbitrary commands to execute with Bitcoin Core process privileges. Version 32 changes wallet-notification placeholder replacement so wallet names are treated as literal text and tightens wallet naming by rejecting certain relative-path names containing . or .. path elements. A second issue emerged during review of Bitcoin Core's rewritten HTTP server, which was audited using Moonshot AI's Kimi K3 model and identified a memory-exhaustion path where 16 unauthenticated REST connections could push memory use from 46 MB to approximately 3 GB in roughly one minute. After the revised fix, the same test increased memory use by only 3 MB over 90 seconds, compared with 3.2 GB before the patch.
The update replaces Bitcoin Core's existing web server with a new version that underwent Moonshot AI's Kimi K3 model audit. The rewritten HTTP server is replacing libevent in version 32 and addresses a memory-exhaustion scenario where the server could accumulate client data faster than clearing it, creating potential for unlimited memory usage. The patch was merged on September 5, before v32.0rc1 was tagged, ensuring the memory problem was resolved before version 32's shipping. The new server has not yet appeared in a stable Bitcoin Core release, and the specific flaw was caught before the server appeared in a stable release. The use of Kimi K3 fits a recent pattern of AI-assisted security review across Bitcoin software, with Bitcoin Red Team logging 7,958 potential findings after scanning hundreds of Bitcoin-related open-source projects.
