The October 2 emergency action blocks new Stylus code from becoming callable. Existing applications remain active, while a separate safeguard covers settlement to Ethereum.
Developers seeking to bring new Stylus applications online on Arbitrum are facing a pause. The Security Council’s October 2 action temporarily blocked new contract activations on Arbitrum One and Nova. Already-active contracts continue to run; the measure has not shut down either network.
The Council’s report points to increasingly sophisticated AI-assisted attacks using hand-crafted WebAssembly (WASM) programs outside the standard Stylus compiler toolchain. The identified bugs primarily threaten the chain’s ability to keep processing. According to the report, no attack enabling theft of user funds had been discovered.
“Existing contracts are not paused.”
Arbitrum Security Council report, October 2, 2026
New releases wait while existing applications keep running
Activation is the step that makes deployed Stylus code callable. Blocking that step affects both a new smart contract and an application update that requires fresh activation. An expired program cannot be reactivated during the pause either.
The Council implemented the restriction by making the gas requirement for new activations prohibitively high. On the Stylus side, this was a configuration change rather than a further ArbOS software upgrade. Earlier ArbOS releases had already patched several bugs reported over recent months.
Arbitrum’s developer notice says active programs can still be called until they expire, and their lifetime can be extended through keepalive before expiration. Deployment and execution of Solidity-based EVM contracts are unaffected.
A date specific to Arbitrum One: The report says ArbOS 61 renewed all active Stylus contracts on that network, so none of those currently active contracts expires before August 20, 2027. It does not give the same assurance for Nova. Developers need to check their network and the remaining lifetime of their own contracts.
A separate, conditional safeguard for withdrawals
The second part of the emergency action adds a guard to Arbitrum One’s BoLD dispute system. Anyone can trigger a settlement pause on Ethereum by demonstrating that two conflicting answers to the same proof step have both been accepted as valid.
If the guard is triggered, Arbitrum One will keep processing transactions. Unconfirmed messages to Ethereum, including withdrawals, would wait until a fix is deployed. In a layer 2 rollup, executing transactions and settling them on the base chain are distinct steps; the safeguard acts on the latter.
Installing the guard does not mean withdrawals are currently frozen across the network. The Stylus activation restriction is already in effect, whereas the BoLD guard responds to a specific proof conflict. Describing both as a general network shutdown would obscure what users and developers can still do.
No date has been announced for reopening new activations. The Arbitrum Foundation will discuss the timing and conditions with the DAO. The decision illustrates why assessing rollup exit routes and upgrade authority involves more than comparing transaction fees. Further announcements will be covered in our blockchain news section.
