Arbitrum’s Safety Council briefly blocked new Stylus contract activations on Arbitrum One and Nova in an October 2 emergency motion, limiting applications and app updates that require recent activation. Already-active Stylus functions can preserve operating, whereas bizarre Solidity contract deployment and execution stay unaffected, in keeping with the Council’s motion report.
Arbitrum attributed the precaution to more and more refined AI-assisted assaults involving hand-crafted WebAssembly applications outdoors the usual Stylus compiler toolchain. It stated identified Stylus bugs primarily threaten chain liveness, together with denial-of-service dangers, and that no assault allowing theft of consumer funds had been found.
The linked Ethereum, Arbitrum One and Nova transaction information present profitable execution on October 2, round 15:30 to fifteen:31 UTC.
For builders, the excellence is between storing code and making it usable. Stylus contracts run WebAssembly applications, which want activation to change into executable. Arbitrum’s documentation distinguishes that step from deployment, which shops code onchain. New contract situations utilizing similar program code can reuse an present activation, supplied it’s nonetheless legitimate.
A brand new software model requiring recent activation can’t change into executable in the course of the pause. Reactivating an expired program, or one needing reactivation after a Stylus model change, can also be blocked, the Council stated. The scope is activation, quite than a blanket prohibition on deploying each new contract occasion.
Present applications stay callable till expiration. Builders can proceed extending an energetic program’s lifetime via the permissionless keepalive renewal mechanism earlier than it expires, in keeping with the official pause discover. This leaves renewal accessible whereas reactivation of an already-expired program is blocked.

The Council stated it applied the restriction by elevating the activation fuel requirement to a prohibitively costly stage. It described this as a configuration change requiring no improve to ArbOS, the community’s working software program.
When withdrawals may wait
The identical emergency motion put in a separate safeguard for BoLD’s one-step proofs on Arbitrum One. Anybody can current two conflicting solutions to the identical step of an open problem. If the one-step proof accepts each, the guard places One’s settlement to Ethereum on maintain, in keeping with the Council.
Arbitrum says One would proceed processing usually throughout that suspension. Nevertheless, messages from One to Ethereum that haven’t but been confirmed, together with withdrawals, must wait whereas the Council deploys a repair and resumes settlement. Putting in the guard doesn’t itself pause withdrawals; the delay relies on its battle situation being met.
For builders ready to activate new Stylus code, reopening stays the subsequent determination. The October 2 report and developer discover give no date, saying the Basis will work with ArbitrumDAO on the timeline and method of restoring activations.








