nimiq-blockchain: Peer-triggerable panic during history sync

Impact

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.

Patches

The patch for this vulnerability is included as part of v1.3.0.

Workarounds

No known workarounds.