Arbitrum Pauses New Stylus Activations Amid AI-Assisted Attack Concerns

Arbitrum has paused new Stylus contract activations on Arbitrum One and Nova after AI-assisted attacks made it easier to build attacks against 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 attacks were designed to degrade chain performance for other users, but no attack that enables the theft of user funds has been found. Recent ArbOS releases patched several reported bugs and known attacks, and the pause is meant to prevent developers from activating new hand-crafted WASM programs while the network may still be exposed to unpatched variants.

Arbitrum has raised the gas required to activate a Stylus contract to a level intended to make new activations effectively unusable. The change does not require an ArbOS upgrade or a separate external audit. The Security Council also added a guard for Arbitrum One's one-step proof of BoLD, which can receive two conflicting answers to the same step of an open challenge.

The immediate effect is on deployment rather than use: Arbitrum will work with ArbitrumDAO on the timing and method for restoring activations, but no end date has been announced. Users do not need to withdraw from active contracts because of the pause itself: the contracts remain live, their renewals continue, and the known attack is aimed at chain availability rather than fund theft.