Bitcoin Core, one of the fundamental software implementations supporting the Bitcoin network, publicly disclosed the technical details of three security vulnerabilities on November 10, 2026. According to a November 11 report by The Block, one of the vulnerabilities was classified as high severity, while the other two were rated medium severity. Under certain conditions, the flaws could prevent mining nodes from generating blocks, delay block processing, or grant excessive privileges to Tor connections. Developers confirmed that all three vulnerabilities had already been addressed through software updates released in October 2025.
How Did the High-Severity Vulnerability Affect Bitcoin Miners?
According to Bitcoin Core's official security disclosure, the vulnerability identified as CVE-2025-62861 could occur during a blockchain reorganization on the Bitcoin network.
The issue caused inconsistencies when Bitcoin Core reevaluated certain transactions stored in its mempool.
Under specific circumstances, the software could become unable to generate valid block templates.
Mining nodes experiencing this issue had to be restarted.
The vulnerability affected Bitcoin Core versions 28.0 through 28.2 and 29.0 through 29.1.
The issue was reported by Niklas Goegge on September 26, 2025, and was subsequently fixed in Bitcoin Core versions 30.0 and 29.2.
Developers publicly disclosed the technical details approximately one year after the fixes were released.
Two Additional Security Vulnerabilities Revealed
The second disclosed security vulnerability was registered as CVE-2025-62859.
According to Bitcoin Core's technical disclosure, the flaw could allow a malicious network participant to delay block processing under certain conditions.
An attacker could delay the processing of blocks by approximately 10 minutes.
In certain network configurations, the attack could also be repeated.
The third vulnerability was disclosed under the identifier CVE-2025-62860.
This issue caused certain connections arriving through the Tor network to be incorrectly classified as trusted connections.
BitcoinCore developers reported that thousands of reachable mainnet nodes were granting excessive privileges to incoming Tor connections because of specific configuration settings.
However, the issue did not affect all Bitcoin nodes running their default configurations.
The official security advisory specified that the vulnerability applied only to nodes using certain -whitelist settings.
Bitcoin Core Updates Had Already Been Released
Developers confirmed that all three security vulnerabilities were fixed in Bitcoin Core version 30.0.
That version was released on October 10, 2025.
Bitcoin Core 29.2 was subsequently released on October 14, 2025.
The disclosure made by developers on November 10, 2026, therefore represents the public release of information about previously patched security issues rather than the discovery of a new, unpatched attack.
This distinction is important for accurately assessing the current security status of the Bitcoin network.
Kriptofoni Assessment
Bitcoin Core's disclosure of three security vulnerabilities highlights the importance of security audits in open-source blockchain software.
The high-severity issue, particularly because of its potential impact on mining operations, demonstrates why keeping node software up to date is essential.
However, the fact that the vulnerabilities had already been patched is an important consideration.
The disclosures do not mean that the Bitcoin network is currently under attack because of these three vulnerabilities.
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Disclaimer: This content is for informational purposes only and is not investment advice. Cryptocurrencies are high-risk; make investment decisions based on your own research.
Content Editor and Writer
Dr. Mesut İnan is a researcher, academic and crypto journalist who has been producing content about cryptocurrencies since 2018. He brings a different perspective to the industry by combining his expertise in sociology with the cryptocurrency ecosystem. Before joining Kriptofoni as co-founder, content editor and writer, İnan worked for several cryptocurrency media platforms: he was an editor and writer at Kriptokoin from 2018 to 2023 and at COINTURK from 2023 to 2024. İnan made a valuable contribution to the ecosystem with his book on Bitcoin, "Bitcoin Sen Bizim Her Şeyimizsin" (Bitcoin, You Are Our Everything). Alongside his academic background, his regular analyses, news and commentary have made him one of the well-known names in cryptocurrency journalism in Turkey. İnan continues his work as a writer and educator and remains a prominent expert voice in the cryptocurrency field.
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