Arbitrum Halts New Stylus Deployments Amid AI-Assisted Attack Risk

Arbitrum has paused new Stylus contract activations on Arbitrum One and Nova after AI-assisted attacks targeted hand-crafted WASM programs.

The Security Council completed the emergency action at 11:30 EST on 2 October 2026, blocking new deployments but not stopping existing Stylus contracts from running or users from interacting with them.

The known Stylus bugs mainly threaten chain liveness, meaning the network's ability to keep processing transactions. A denial-of-service attack can make that difficult even without taking a user's funds.

Arbitrum worked with the Security Council to change one configuration setting on each chain, raising the gas required to activate a Stylus contract to a level intended to make new activations effectively unusable.

The change also added a guard for Arbitrum One's one-step proof of BoLD, the system used to confirm the chain's state before settlement to Ethereum.