Bitcoin Core disclosed a configuration flaw on Nov. 10 that precipitated hundreds of reachable Bitcoin mainnet nodes to deal with incoming Tor connections as trusted friends, giving them exemptions from denial-of-service limits and privateness protections.
The mission rated CVE-2025-62860 medium severity. It affected susceptible releases when a non-default -whitelist setting lined the IP handle of the node’s Tor daemon, the software program dealing with its Tor connections. Nodes that by no means enabled that setting had been by no means affected.
The fixes shipped in October 2025. The brand new disclosure explains how a configuration meant for trusted connections unfold by means of bundled software program and granted these privileges to distant Tor friends.
For an incoming Tor connection, Bitcoin Core sees the Tor daemon’s IP handle quite than the distant peer’s precise community handle. That daemon often runs on the identical machine or native community.
On affected configurations, Core checked that handle in opposition to an IP vary marked as trusted. If the vary included the daemon, incoming Tor connections inherited the whitelist permissions. The native handle recognized the middleman carrying the connection, however couldn’t set up which distant peer deserved belief.
What modifications on the belief test
A susceptible launch used the daemon’s matching IP vary to grant trusted-peer exemptions.
Incoming onion connections bypass address-based whitelist matching, stopping this mistaken grant.
The patch excludes incoming onion connections from address-based whitelist grants.
Earlier than-fix state requires a susceptible launch and a non-default whitelist matching the Tor daemon. The change issues address-based -whitelist permissions, not each doable peer permission.
That distinction issues as a result of -whitelist lifts varied limits meant to limit denial-of-service conduct, together with mitigations in opposition to privateness leaks. The difficulty involved exemptions granted to community friends; the privileges described within the disclosure don’t set up pockets entry or coin theft.
Bitcoin Core says well-liked distributors bundled the node software program with Tor and an identical whitelist vary. Some consumer software program additionally required whitelisting and generally ran alongside Tor. Collectively, these configurations led hundreds of reachable mainnet nodes to whitelist each incoming Tor connection.
That’s the advisory’s historic publicity discovering, not a rely of nodes nonetheless susceptible at the moment.
Martin Zumsande and Antoine Poinsot reported the problem in September 2025. The patch merged on Sept. 17 and stopped making use of address-based whitelist permissions to incoming onion connections, whose distant community addresses are hid.
Bitcoin Core 30.0, 29.2 and 28.3 shipped the repair in October 2025. The repair is current in all variations from 30.0 onward, in addition to later minor releases within the mounted 28.x and 29.x branches.
What node operators ought to test now
These older patch thresholds are separate from at the moment’s improve steering. Bitcoin Core’s upkeep schedule now covers 30.x, 31.x and 32.x; 28.x and 29.x have reached finish of life. The mission recommends the most recent upkeep launch of the latest main model an operator can undertake. Its obtain web page lists 32.1 as newest as of Nov. 11.
For operators utilizing packaged node software program, test the Bitcoin Core model truly working and whether or not its whitelist vary consists of the Tor daemon’s handle.
