ARB Plunges 6.5% on Arbitrum Security Upgrade

Arbitrum's ARB token fell 6.5% after an emergency security upgrade paused new Stylus contract activations on October 2, 2026.

The upgrade was a proactive measure to address vulnerabilities in handwritten WebAssembly programs and Stylus contracts that could degrade chain liveness but did not threaten user funds.

The action increased perceived protocol risk, causing traders to sell ARB despite the lack of any credible reports of user fund losses or an ongoing hack.

The broader crypto market was mildly risk-off during the same period, with the total market cap falling 2% and Bitcoin (BTC) down around 3%.