wrong miner tx in block in logs

[j-berman]

Reported by a few people in the stressnet channel:

2025-11-07 02:12:18.998	I Synced 2870785/2870970 (99%, 185 left)
2025-11-07 02:12:19.109	E wrong miner tx in block: <fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596>, b.miner_tx.vin.size() != 1
2025-11-07 02:12:56.387	I Synced 2870788/2870970 (99%, 182 left)
2025-11-07 02:12:56.471	E wrong miner tx in block: <fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596>, b.miner_tx.vin.size() != 1
2025-11-07 02:13:20.441	I Synced 2870791/2870970 (99%, 179 left)
2025-11-07 02:13:20.537	E wrong miner tx in block: <fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596>, b.miner_tx.vin.size() != 1

The node who sends it gets banned.

[jeffro256]

My node also receives this fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596 transaction every several days.

[jeffro256]

I'll run a patch on my node which dumps the block

Nov 14 edit: still running, it hasn't experienced one of these since i've been running the patch

[Cyrix126]

the same error (same block hash) was reported in 2020, so it's likely not related to recent changes.
monero-project#6419

[Boog900]

As a shot in the dark after seeing that this happened before stressnet I checked what the hash of a block with fields that are defaulted would be, and its this same hash: fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596

rust code with monero-oxide (we recently made the miner_transaction private to ensure it has a miner input so you need to either use an old version or edit monero-oxide to make that field public):

  let block = Block {
    header: BlockHeader {
      hardfork_version: 0,
      hardfork_signal: 0,
      timestamp: 0,
      previous: [0; 32],
      nonce: 0,
    },
    miner_transaction: Transaction::<NotPruned>::V1 {
      prefix: TransactionPrefix {
        additional_timelock: Timelock::None,
        inputs: vec![],
        outputs: vec![],
        extra: vec![],
      },
      signatures: vec![],
    },
    transactions: vec![],
  };

  println!("{:?}", hex::encode(block.hash()));

[Cyrix126]

level 4 log catching it:

[P2P8]  TRACE   blockchain      src/cryptonote_core/blockchain.cpp:1612 Blockchain::get_current_cumulative_block_weight_limit
[P2P8]  TRACE   blockchain      src/cryptonote_core/blockchain.cpp:4989 Blockchain::add_new_block
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:407  mdb_txn_safe: destructor
[P2P8]  TRACE   blockchain      src/cryptonote_core/blockchain.cpp:3153 Blockchain::have_block_unlocked
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:3747 BlockchainLMDB::block_exists
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:3758 Block with hash fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596 not found in db
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:5891 BlockchainLMDB:: get_alt_block
[P2P8]  TRACE   blockchain      src/cryptonote_core/blockchain.cpp:820  Blockchain::get_tail_id
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:4258 BlockchainLMDB::top_block_hash
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:4288 BlockchainLMDB::height
[P2P8]  TRACE   blockchain.db.lmdb      src/blockchain_db/lmdb/db_lmdb.cpp:4207 BlockchainLMDB::get_block_hash_from_height
[P2P8]  TRACE   blockchain      src/cryptonote_core/blockchain.cpp:2036 Blockchain::handle_alternative_block
[P2P8]  ERROR   cn      src/cryptonote_basic/cryptonote_format_utils.cpp:1027   wrong miner tx in block: <fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596>, b.miner_tx.vin.size() != 1
[P2P8]  ERROR   verify  src/cryptonote_core/blockchain.cpp:2043 Block with id: fb877ea3400f731c2b948e87655368f1c0486e3c114bb3f8f3839bec1b2f9596 (as alternative), but miner tx says height is 0.

EDIT: using this build: https://github.com/j-berman/monero/actions/runs/19531208476