CVE-2021-31876 log

Source
Severity Medium
Remote Yes
Type Insufficient validation
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.
Group Package Affected Fixed Severity Status Ticket
AVG-1486 bitcoin-daemon 0.21.1-2 Medium Vulnerable
References
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-May/018893.html
https://bitcoinops.org/en/newsletters/2021/05/12/