David Schwartz Proposes XRP Ledger Plan to Stop Front-Running Attacks

Highlights:

• The XRP Ledger could gain a new transaction reservation system to reduce front-running and sandwich attacks.
• David Schwartz says the proposal would let reserved transactions execute before later competing transactions.
• The proposal arrives as XRPL expands its DeFi features and attracts more on-chain trading activity.

David Schwartz, former CTO of Ripple, has proposed a transaction reservation scheme after fresh concerns emerged over front-running and sandwich attacks on the XRP Ledger network. The proposal followed claims that validators and well-connected nodes can inspect pending transactions before a ledger closes.

David Schwartz Proposes Fix For XRPL Front Running

Ripple CTO Emeritus David Schwartz (@JoelKatz) has proposed a new scheme to eliminate front-running and sandwich attacks on XRP Ledger.

The plan introduces a "transaction reservation" system, letting users secure execution… pic.twitter.com/XbJYkPbJXc

— BSCN (@BSCNews) June 29, 2026

David Schwartz said he is not overly concerned because XRP Ledger already uses canonical transaction ordering and mixed execution to reduce front-running opportunities. However, he proposed a transaction reservation system that would make disclosed transactions execute before later transactions could target them.

The discussion started after XRPresso claimed validators and well-connected nodes can inspect pending transactions in XRPL’s pre-validation queue before a ledger closes. According to the post, they can analyze pending trades, identify profitable opportunities, and repeatedly submit transactions to improve their final position.

A serious front-running issue continues on the XRPL that disadvantages regular users.

Validators and well-connected nodes can view transactions in the pre-validation queue before a ledger closes.

They can quickly analyze a pending trade, determine if front-running or…

— XRPresso.io (@xrpresso_io) June 29, 2026

XRPresso said the concern mainly affects users trading through wallets and decentralized applications. The group also said payments, offer crossing, decentralized exchange trades, and automated market maker swaps could all face front-running and sandwich attack risks. XRPresso argued that repeated transaction submissions may improve an attacker’s chances of landing near a target trade because each ledger follows a deterministic ordering process.

Official XRP Ledger documentation says the ordering process remains efficient and difficult to manipulate. However, the same documentation states that determined actors can still attempt front-running even though the network makes such attacks difficult.

New Execution Model Could Strengthen XRP Ledger

Schwartz acknowledged the community’s concerns but said XRP Ledger already prevents many front-running attempts before transactions reach the final ledger. Even so, he said the network could further reduce the remaining risk through a simple transaction reservation mechanism.

David Schwartz proposed a new ledger object called ReservedTxns to store transaction IDs for a specific future ledger. He also introduced a new transaction type called TxnReserve that users would submit to reserve an execution slot before broadcasting the actual transaction. The proposal aims to stop validators and other network participants from reacting to a transaction after it becomes visible but before execution.

The proposal requires users to pay at least twice the standard transaction fee to reserve an execution slot in a future ledger. Users can reserve execution slots only for future ledgers, and each reservation must target a ledger no more than 16 ledgers ahead. Each ReservedTxns object would store up to 32 transaction IDs to keep the reservation system efficient under the current proposal.

David Schwartz said XRP Ledger software should hold reserved transactions instead of broadcasting them immediately. The software would release each transaction only after the previous ledger’s consensus set becomes known. That timing would prevent validators and traders from submitting competing transactions after viewing the reserved transaction. When the target ledger arrives, the network would first check for a ReservedTxns object.

David Schwartz Links Proposal to Growing DeFi Activity

David Schwartz introduced the proposal as XRPL developers continue expanding the network’s decentralized finance ecosystem with new trading and lending features. The XRPL Foundation recently introduced a draft proposal for AMM Swappable Curves. The upgrade would add StableSwap and concentrated liquidity options to the native automated market maker.

Those upgrades could increase decentralized trading, lending, token settlements, and overall transaction activity across the XRP Ledger. Ripple and JPMorgan recently demonstrated a tokenized U.S. Treasury settlement on the XRP Ledger, highlighting growing institutional interest in blockchain-based asset settlement. The proposal also comes a month after David Schwartz warned XRPL users about a sharp rise in fake XRP giveaway scams and wallet drainer attacks.