Bitcoin Core: private-broadcast linking fix in 32.x, 31.x backport still open
Serguey Asael Shinder2 min readBitcoin Core has merged a privacy fix for its private broadcast feature into the 32.x branch, while the backport to the current stable line, 31.x, is still an open pull request as of 9 October. Private broadcast is opt-in and off by default, so the issue concerns only nodes that enabled it.
What private broadcast does. With the privatebroadcast option, transactions submitted through sendrawtransaction are sent over dedicated, short-lived connections to Tor or I2P peers, or to IPv4/IPv6 peers through Tor, so the node's own address is not tied to the transaction it originates.
The problem. Bitcoin Core "discourages" misbehaving peers. Reviewers of the original fix pointed out that discouraging a private-broadcast peer could change node behaviour in a way visible from outside, and that normal discouragement of an address could also drop other connections to the same address. Those shared effects give an observer a clue for linking the private connection to the node's ordinary connections — exactly what the feature exists to prevent.
The fix ("net: don't discourage private broadcast peers") separates the two: private-broadcast peers are excluded from normal discouragement but are still disconnected if they misbehave, and discouraging an ordinary peer no longer disconnects private-broadcast connections that share its address. The change reached the main branch on 25 September and the 32.x branch via PR 36312 on 1 October. The 31.x backport, PR 36358, carries a 31.2 milestone and received an approval from reviewer vasild on 6 October; a milestone is not a release date.
Not the same as the 31.1 fix. Bitcoin Core 31.1 already repaired an earlier leak in which private-broadcast connections could fall back to clearnet instead of the privacy network. That was about routing; the new change is about observable peer handling. Developers have also marked private broadcast as experimental and narrowed its privacy claims to risk reduction.
What to do. The official download page still lists 31.1 as current; 32.0 exists only as release candidates (rc3 binaries dated 6 October). Users who rely on private broadcast on 31.1 can wait for 31.2 or test a 32.0 candidate — and in the meantime should treat the feature as reducing, not removing, linkability.
Sources: bitcoin/bitcoin pull request 36358, "[31.x] net: don't discourage private broadcast peers" — https://github.com/bitcoin/bitcoin/pull/36358 ; pull request 36312 — https://github.com/bitcoin/bitcoin/pull/36312 ; CryptoSlate report, 8 October 2026 — https://cryptoslate.com/bitcoin-cores-privacy-fix-reaches-v32-code-while-the-v31-patch-remains-open/