Mempool Pinning
A tactic that makes an unconfirmed transaction difficult to replace or fee-bump, delaying confirmation.
Mempool pinning occurs when a transaction is structured so policy limits make replacement or fee-bumping difficult. It is usually not a consensus attack: the transaction may be valid, but nodes and miners may refuse the replacement or package needed to move it quickly.
Wallets reduce pinning risk by keeping dependency chains simple, avoiding unnecessary shared inputs, and using fee-bumping strategies that match current relay policy. Package relay improvements can help nodes evaluate related transactions together, but support varies by network and implementation.
Related terms
4 linkedExplore connected entries beyond the alphabetical index.
Mempool
→A temporary storage space in a node for pending transactions that have not yet been included in a confirmed block.
CPFP
→A fee-bumping technique where a new transaction spends an unconfirmed output and pays a high fee to incentivize miners to include both.
Replace By Fee (RBF)
→A Bitcoin node policy (BIP125) allowing an unconfirmed transaction to be replaced by a new one that pays a higher fee.
Package Relay
→The ability for nodes to relay groups of related transactions together so miners evaluate fees on the package total.
All terms and definitions may update as the Cryptionary improves.
