Bitcoin Core Discloses Three Patched Vulnerabilities Affecting Mining and Network Security
Developers revealed technical details of security flaws impacting mining operations and Tor network privacy.
1Disclosure of Patched Flaws
Bitcoin Core officially disclosed three security vulnerabilities on November 10, 2026, after previously issuing patches in October 2025. These defects, identified as CVE-2025-62861, CVE-2025-62859, and CVE-2025-62860, were kept confidential until the end-of-life status for version 29.x. None of the issues resulted in unauthorized coin creation or actual network consensus failure.
2Mining Node Operational Risk
The most severe vulnerability, CVE-2025-62861, affected Bitcoin Core versions 28.0 through 29.1. It triggered mempool inconsistencies during blockchain reorganizations, specifically involving TRUC transactions. Affected mining nodes could fail to validate block templates, forcing operators to restart their software to resume mining work and avoid forfeiting potential transaction fees.
3TRUC Transaction Logic Error
The bug stemmed from sibling eviction logic that failed to account for the bypass_limits flag during chain reorganizations. While TRUC transactions are governed by BIP-431 relay policies rather than consensus rules, the flaw caused the mempool to incorrectly evict transactions. This left nodes unable to generate valid work until a manual restart.
4Compact Block Processing Delay
A medium-severity flaw, CVE-2025-62859, allowed attackers to manipulate transaction witnesses within compact blocks. By exploiting improper handling of these blocks, malicious peers could delay block processing by up to ten minutes. This attack was particularly effective against nodes running with the blocksonly parameter or those connected to compromised high-bandwidth peers.
5Tor Connection Security Risks
The third vulnerability, CVE-2025-62860, involved Tor daemon configurations. When operators used the -whitelist setting to include their Tor address, incoming connections could inherit trusted-peer privileges. This weakened denial-of-service protections and privacy safeguards. Thousands of reachable mainnet nodes were potentially exposed, though standard installations remained unaffected by this specific configuration error.
6Coordinated Disclosure Timeline
Niklas Goegge reported the mining defect in September 2025, while Eugene Siegel identified the compact block issue in April 2025. Developer Greg Sanders authored the necessary corrections. These fixes were integrated into versions 30.0, 29.2, and 28.3 by October 2025, following the project's established embargo process for sensitive security disclosures.
7Operational Impact and Scope
Despite the patches, approximately 9% of reachable nodes were still running vulnerable versions at the time of the public disclosure. The vulnerabilities highlight how obscure transaction-handling defects can create tangible operational hurdles for miners. However, the Bitcoin network itself remained secure, as these issues did not compromise underlying consensus rules.
8Broader Market Context
The disclosure occurred amid volatile market conditions, with Bitcoin prices fluctuating following hotter-than-expected U.S. inflation data. While the software maintenance issues caused concern for node administrators, they were distinct from broader macroeconomic pressures. The incident underscores the necessity of regular software updates to maintain node efficiency and network privacy.