Arbitrum pauses new Stylus activations in emergency security action

On October 2, 2026, the Arbitrum Security Council executed an emergency upgrade on Arbitrum One and Nova, pausing new activations of Stylus contracts. The action preemptively blocks unpatched WebAssembly programs that could trigger denial-of-service liveness bugs. Existing contracts remain active, but new deployments are delayed indefinitely. The upgrade also added a guard to Arbitrum One's BoLD dispute system, which could delay unconfirmed withdrawals if contradictory proofs are accepted.

Details and impact of the Stylus pause

• ▪Existing Stylus contracts that are already live on Arbitrum One and Nova are unaffected by the October 2, 2026 Stylus activation pause, allowing them to continue executing and being renewed
• ▪The Arbitrum Security Council executed an emergency upgrade on October 2, 2026, at 11:30 EST, pausing all new activations of Stylus contracts on the Arbitrum One and Nova chains

BoLD guard implementation on Arbitrum One

• ▪The newly implemented BoLD guard can delay unconfirmed withdrawals on Arbitrum One if the dispute system ever accepts contradictory proofs
• ▪The Arbitrum Security Council's October 2, 2026 emergency upgrade added a permissionless guard to the BoLD one-step proof dispute resolution mechanism specifically on the Arbitrum One chain

Debatable claims

• ▪Arbitrum's pause on new Stylus activations does more harm than good to the ecosystem
• ▪WebAssembly-based smart contract frameworks pose unacceptable security risks to layer-2 networks
• ▪The Arbitrum Security Council is justified in bypassing DAO governance to address network liveness issues
• ▪Delaying unconfirmed withdrawals is an acceptable price to pay for securing Arbitrum's dispute system