Advisories for Cargo/Nimiq-Blockchain package

The validity store treats a transaction with stored block_number = X as "in window" only when X > last_bn - transaction_validity_window_blocks (strict inequality). However the protocol's Transaction::is_valid_at accepts a transaction for inclusion in any block in [validity_start_height - blocks_per_batch, validity_start_height + window - 1]. By choosing validity_start_height = X + blocks_per_batch (the largest value still compatible with first inclusion at block X), an attacker can replay the same signed transaction …

A remote peer can crash any full node by sending a RequestBatchSet message containing the genesis block's hash. The handler calls get_epoch_chunks which iterates backwards through macro blocks using Policy::macro_block_before. When it reaches the genesis block number, macro_block_before panics with "No macro blocks before genesis block".

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 …

Block timestamp validation enforces that timestamp >= parent.timestamp for non-skip blocks and timestamp == parent.timestamp + MIN_PRODUCER_TIMEOUT for skip blocks, but there is no visible upper bound check against the wall clock. A malicious block-producing validator can set block timestamps arbitrarily far in the future. This directly affects reward calculations via Policy::supply_at() and batch_delay() in blockchain/src/reward.rs, inflating the monetary supply beyond the intended emission schedule.