Key Highlights
- Bitcoin Core addressed three security vulnerabilities affecting transaction handling, compact-block downloads, and Tor-related peer permissions.
- The fixes were included in Bitcoin Core 30.0, 29.2, and 28.3, although about 9% of reachable nodes were still running vulnerable versions around the disclosure date.
- None of the vulnerabilities enabled bitcoin theft, unauthorized coin creation, or a consensus failure, and no exploitation was reported.
Bitcoin Core Fixed Three Security Vulnerabilities
Bitcoin Core addressed three security vulnerabilities disclosed in November 2025, including a mining-related defect reported by security researcher Niklas Goegge on Sept. 26, 2025. Developer Greg Sanders introduced a correction that was merged on Oct. 2 and prevented problematic transaction eviction behavior during blockchain reorganizations.
The correction was included in Bitcoin Core 30.0, 29.2, and 28.3 during October 2025. Despite the releases, approximately 9% of reachable Bitcoin nodes continued to advertise vulnerable software versions around the disclosure date, highlighting the ongoing challenge of coordinating upgrades across the decentralized network.
Other Bitcoin Core Vulnerabilities Included Compact Blocks and Tor Permissions
The second vulnerability, CVE-2025-62859, received a medium-severity classification and involved maliciously constructed compact blocks. An attacker could exploit improper handling of modified transaction witnesses to repeatedly delay block downloads. Under certain network conditions, including compromised high-bandwidth peer connections, the disruption could continue indefinitely.
Researcher Eugene Siegel identified CVE-2025-62859 in April 2025. Gregory Sanders developed the fix, which was incorporated into Bitcoin Core 30.0 and 29.2.
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The third issue, CVE-2025-62860, involved inbound Tor connections and trusted-peer permissions. If operators configured Bitcoin Core’s optional -whitelist setting to include the address of their Tor daemon, incoming connections could mistakenly receive privileges intended for trusted peers.
Those exemptions weakened certain denial-of-service protections and privacy safeguards. Bitcoin Core said that thousands of reachable mainnet nodes were potentially affected, although standard configurations remained safe.
Why Bitcoin Core Disclosed the Vulnerabilities in November
The Nov. 10 announcements followed Bitcoin Core’s established vulnerability-disclosure schedule. Developers withheld technical details until the final vulnerable major release line, 29.x, reached end-of-life status on Oct. 27, 2026. The issues therefore followed the conventional embargo process rather than the approach used for three AI-assisted vulnerability disclosures published on Oct. 28.
None of the three vulnerabilities allowed attackers to steal bitcoin, create coins without authorization, or trigger a consensus failure. Bitcoin Core also reported no exploitation. The mining-related vulnerability required specific blockchain reorganization conditions, limiting its effects to affected operators rather than the Bitcoin network itself.
Why This Matters
For bitcoin miners and node administrators, the disclosures demonstrate why software maintenance remains important even when a vulnerability cannot directly compromise funds. Operational weaknesses can still interfere with block downloads, affect node protections, or create problems during unusual network conditions.
The episode also shows how narrowly scoped transaction-handling defects can produce tangible consequences without threatening Bitcoin’s underlying consensus rules. Updating to a fixed Bitcoin Core release remains the relevant mitigation for operators running affected versions.
Frequently Asked Questions
Which Bitcoin Core versions included the fixes?
The fixes were included in Bitcoin Core 30.0 and 29.2. The mining-related correction also appeared in version 28.3.
Did the vulnerabilities allow bitcoin theft?
No. None of the vulnerabilities enabled bitcoin theft, unauthorized coin creation, or a consensus failure, and no exploitation was reported.
How many nodes were affected?
Approximately 9% of reachable nodes continued advertising vulnerable versions around the disclosure date. Bitcoin Core also said that thousands of reachable mainnet nodes were potentially affected by the Tor-related permissions issue, while standard configurations remained safe.
