nimiq-blockchain provides persistent block storage for Nimiq's Rust implementation. Prior to version 1.3.0, HistoryStore::put_historic_txns uses an assert! to enforce invariants about HistoricTransaction.block_number (must be within the macro block being pushed and within the same epoch). During history sync, a peer can influence the history: &[HistoricTransaction] input passed into Blockchain::push_history_sync, and a malformed history list can violate these invariants and trigger a panic. extend_history_sync calls this.history_store.add_to_history(..) before comparing the computed history root against the macro block header (block.history_root()), so the panic can happen before later rejection checks run.

The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available.