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.