btcd before 0.24.0 does not correctly implement the consensus rules outlined in BIP 68 and BIP 112, making it susceptible to consensus failures. Specifically, it uses the transaction version as a signed integer when it is supposed to be treated as unsigned. There can be a chain split and loss of funds.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-34478
• https://delvingbitcoin.org/t/disclosure-btcd-consensus-bugs-due-to-usage-of-signed-transaction-version/455
• https://github.com/btcsuite/btcd/blob/e4c88c3a3ecb1813529bf3dddc7a865bd418a6b8/blockchain/chain.go#L383C1-L392C3
• https://github.com/btcsuite/btcd/blob/e4c88c3a3ecb1813529bf3dddc7a865bd418a6b8/txscript/opcode.go#L1172C1-L1178C3
• btcsuite/btcd#1981
• btcsuite/btcd@253b688