At this Ethereum Engineering Group online event, Thisal de Silva will talk about Polygon CDK, a modular toolkit for deploying EVM-compatible L2 chains, and its shared ZK proving system.
Polygon zkEVM includes an egress hatch, a censorship-resistance mechanism that lets users force transactions through L1 when the sequencer is unavailable or censoring. We show how this safety feature can itself be weaponized. We introduce H-ZARE (Heterogeneous zkEVM Arithmetized Root Equivalence), a vulnerability class affecting the Polygon zkEVM validity proof system and by extension every chain built on Polygon CDK. H-ZARE arises when the ZK prover’s arithmetization accepts a transaction that the execution client rejects, producing a state change that violates the EVM specification yet carries a cryptographically valid proof. We demonstrate how an attacker can exploit this divergence through the egress hatch to execute a double-spend, prove a Token Conservation Violation theorem showing the resulting token surplus is irreducible, and report empirical confirmation of phantom proof generation on a pre-patch zkProver.
The talk closes by reflecting on what this vulnerability class reveals about the broader challenges of zkEVM engineering: rapid development cycles, documentation gaps, and the lack of systems-level thinking, and why cross-implementation standardisation is becoming increasingly critical.
🗓 Wednesday, June 24, 2026
🕔 Time: 12:30 PM – 1:30 PM AEST
📍 Zoom call
✨ Ethereum Engineering Group is a meetup for software engineers, computer scientists, researchers, and technologists who want to understand the Ethereum platform and associated technologies. Since March 2020, the Ethereum Engineering Group meetup has been run via Zoom, online. The timing during the day of the meetup depends on who is talking and what part of the world they live in.