Vulnerability identifier: #VU52962

Vulnerability risk: Medium

CVSSv3.1: 4.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-31876

CWE-ID: CWE-840

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Bitcoin Core
Other software / Other software solutions

Vendor: Bitcoin

Description

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to a logic error in Bitcoin Core bip125 logic, related to processing of unconfirmed transactions. A remote attacker can perform state-of-the-art pinning attacks or have other impact on various wallets.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Bitcoin Core: 0.21.0, 0.20.0 - 0.20.1, 0.19.0 - 0.19.2, 0.18.0 - 0.18.1, 0.17.0 - 0.17.2, 0.16.0 - 0.16.3, 0.15.0 - 0.15.2, 0.14.0 - 0.14.3, 0.13.0 - 0.13.2, 0.12.0 - 0.12.1

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External links
http://en.bitcoin.it/wiki/Common_Vulnerabilities_and_Exposures#CVE-2021-31876
http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-May/018893.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.