CVE-2021-31876 Details
Description
Bitcoin Core 0.12.0 through 0.21.1 does not properly implement the replacement policy specified in BIP125, which makes it easier for attackers to trigger a loss of funds, or a denial of service attack against downstream projects such as Lightning network nodes. An unconfirmed child transaction with nSequence = 0xff_ff_ff_ff, spending an unconfirmed parent with nSequence <= 0xff_ff_ff_fd, should be replaceable because there is inherited signaling by the child transaction. However, the actual PreChecks implementation does not enforce this. Instead, mempool rejects the replacement attempt of the unconfirmed child transaction.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://bitcoinops.org/en/newsletters/2021/05/12/ | CVE | Vendor Advisory |
| https://bitcoinops.org/en/topics/replace-by-fee/ | CVE | Vendor Advisory |
| https://en.bitcoin.it/wiki/Common_Vulnerabilities_and_Exposures#CVE-2021-31876 | CVE | Third Party Advisory |
| https://github.com/bitcoin/bitcoin | CVE | Third Party Advisory |
| https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-May/018893.html | CVE | Mailing ListThird Party Advisory |
| https://bitcoinops.org/en/newsletters/2021/05/12/ | [email protected] | Vendor Advisory |
| https://bitcoinops.org/en/topics/replace-by-fee/ | [email protected] | Vendor Advisory |
| https://en.bitcoin.it/wiki/Common_Vulnerabilities_and_Exposures#CVE-2021-31876 | [email protected] | Third Party Advisory |
| https://github.com/bitcoin/bitcoin | [email protected] | Third Party Advisory |
| https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-May/018893.html | [email protected] | Mailing ListThird Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| bitcoin bitcoin | >= 0.12.0, <= 0.21.1 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Nov 21, 2024 | CVE Modified | CVE |
| May 14, 2024 | CVE Modified | [email protected] |
| May 26, 2021 | Initial Analysis | [email protected] |