Securing Ethereum at the protocol layer.
I'm Antoine James — a security researcher at the Ethereum Foundation, where I help run the Protocol Security bug bounty program and hunt vulnerabilities in the clients and specifications that run the network.
Findings
Responsibly disclosed vulnerabilities across Ethereum execution clients, consensus clients, and protocol specifications.
Critical
Chess.com
Payment System BypassUnauthorized premium subscription access via a payment-flow flaw.
Low
Reth
EIP-2681 Nonce ValidationMissing nonce validation lets invalid transactions enter the pool.
Medium
Besu
P256 Curve Point ValidationMissing on-curve validation in P256Verify causes block import failures.
Low
Geth
EIP-2935 Constant MismatchVerkle testing constant doesn't match the hardcoded 0x1FFF bytecode value.
Low
Reth
Missing Malicious Peer PunishmentNo penalty for peers spamming unwanted transaction hashes.
Medium
Consensus Specs
Builder Withdrawal GriefingRepeated 1 ETH deposits lock a builder's withdrawable balance.
Low
Lighthouse
Unsorted Data Columns in KZGColumns not sorted before KZG, breaking cell-index ordering.
Info
Consensus Specs
Fulu DAS Parameter OrderingSwapped parameter order in the DAS index functions.
Low
Lighthouse
Memory Leak in Column SidecarsMissing cache pruning leaks ~7MB/day on long-running beacon nodes.
Experience
Ethereum Foundation
Security Researcher · Protocol Security- Protocol security research across Execution Clients, Consensus Clients, Ethereum specifications, and EIPs.
- Contributed to the Fusaka and Glamsterdam upgrades — reviewing EIPs and their implementation across clients (Go, Rust, Java, …).
- Ran devnet testing with the EthPandaOps team and worked on gas repricing for Fusaka.
- Part of the Bug Bounty Program team — triaging reports, assigning severities, coordinating with client teams, and handling finance payouts.
- Triaged 500+ incoming reports.
- Contributed to building the bounty deposit system, introduced to curb AI-slop submissions.
- Built an automatic AI-Triager: swarms of AI agents that run initial triage, verify findings, and assign severities.
Spearbit
Rust EngineerBackend work on Cantina, Spearbit's competitive audit platform — built profile features like auditors' findings display, optimized and fixed SQL queries, and shipped API and data-layer improvements in Rust.
Formal Land
Security ResearcherFormal verification of the Sui blockchain type-checker and Keccak implementation — translating Rust code to Coq proofs for critical blockchain components.
Let's talk security
Open to protocol security research, audits, and collaboration.