NNEON//FORGE← Vault
SECURITY / INTERMEDIATE / +240 XP

Your transactions are public. Fix that.

Mempool exposure is not a feature. Flashbots exists because default Ethereum is a spectator sport.

Your transactions are public. Every pending transaction in the mempool is visible to every node on the network. Your swap size, your target pool, your slippage tolerance — all public. The mempool is a transparency report you did not consent to.

Flashbots exists because default Ethereum is a spectator sport. MEV searchers watch the mempool, identify profitable transactions, and extract value from them. The victim pays the cost in worse execution. The searcher captures the spread. The validator collects the bribe. Everyone wins except the user.

THE DEEP DIVE

The MEV Supply Chain

The supply chain is simple: a user submits a transaction, a searcher sees it in the mempool, the searcher submits a modified transaction that captures the value, and the validator includes the searcher's transaction instead. The user gets worse execution or no execution at all.

// Default submission (vulnerable)
eth_sendRawTransaction(signedTx)
// -> Broadcast to all peers
// -> Visible in mempool within milliseconds
// -> MEV searchers begin extraction

// Flashbots submission (protected)
eth_sendBundle({
  txs: [signedTx],
  blockNumber: targetBlock,
  minTimestamp: 0,
  maxTimestamp: 0
})
// -> Sent directly to miners/validators
// -> Not broadcast to the network
// -> Included or not, no intermediate state

MEV-Share and the New Protocol

MEV-Share formalizes the relationship between users and searchers. Users submit intents (not transactions) to a matcher. The matcher connects users with searchers who can fulfill the intent while sharing the MEV. The user gets some of the value back. The searcher still profits. The validator still collects fees.

The architectural shift is from "submit a transaction and hope" to "submit an intent and negotiate." The intent is abstract: "I want to swap X for Y at rate Z." The searcher fills in the concrete transaction that satisfies the intent while extracting MEV.

PRINCIPLES

  1. The mempool is not a suggestion box. It is a public auction where you are the item being sold.
  2. Private transaction submission is not about privacy — it is about controlling the information flow.
  3. Flashbots bundles are atomic: all transactions execute together or none execute. Use this to guarantee execution order.
  4. The block builder controls transaction ordering. The block proposer controls which builder wins. Both have incentives.
  5. Timing is a weapon. A transaction that arrives at the right block but the wrong position is still extracted.

IN PRACTICE

Sandwich Attack Prevention

A user submits a large swap through Flashbots. The swap never appears in the public mempool. MEV searchers cannot see it to sandwich it. The user gets the price they expected, not the price the searcher would have set.

Backrun Protection

A protocol submits a liquidation transaction via Flashbots bundle, paired with a follow-up swap. The bundle guarantees execution order: liquidate first, swap second. No searcher can insert a transaction between the two legs.

LIVE SIGNALS

These items surfaced from the intelligence pipeline at generation time.

  • CVE-1999-0095 — The debug command in Sendmail is enabled, allowing attackers to execute commands as root. (NVD / CVE)
  • CVE-1999-1471 — Buffer overflow in passwd in BSD based operating systems 4.3 and earlier allows local users to gain root privileges by specifying a long shell or GECOS field. (NVD / CVE)
  • CVE-1999-1122 — Vulnerability in restore in SunOS 4.0.3 and earlier allows local users to gain privileges. (NVD / CVE)
  • CVE-1999-1506 — Vulnerability in SMI Sendmail 4.0 and earlier, on SunOS up to 4.0.3, allows remote attackers to access user bin. (NVD / CVE)
  • CVE-1999-0084 — Certain NFS servers allow users to use mknod to gain privileges by creating a writable kmem device and setting the UID to 0. (NVD / CVE)

ANTIPATTERNS

  • Sending private transactions to a single relay. diversify across relays for better inclusion rates.
  • Ignoring gas prices in Flashbots bundles. Validators still select bundles by profit.
  • Assuming private submission guarantees inclusion. It does not — it guarantees privacy, not priority.
  • Building MEV protection into the frontend but not the smart contract. A determined attacker bypasses the frontend.

CHECKLIST

  • Large swaps use Flashbots or equivalent private submission
  • Liquidations are submitted as atomic bundles
  • The protocol does not leak intent through mempool analysis
  • Gas price strategies account for MEV extraction costs
  • Users are warned about front-running risks for unprotected transactions

YOUR MOVE

Install the Flashbots Protect RPC. Send a test swap through it. Watch the mempool on Etherscan. Confirm the transaction never appears.