Cursor’s notice of 29 October, updated on 30 October, concerns Anthropic.claude-code versions 2.1.312 and 2.1.313, distributed through the Cursor VS Code Extension Marketplace to Windows and macOS users.
According to Cursor, the malicious versions were not developed by Anthropic. Among other actions, the modified extension attempted to establish persistent SSH access. The notice does not establish that other versions, the official distribution channel or Claude’s web service were affected. Cursor’s official security notice.
Uninstalling the extension may not be enough
Cursor warns that an affected version can leave separate persistence mechanisms on the computer. Simply uninstalling the extension may therefore not resolve the issue. The actual impact depends, among other things, on the installed package, its execution and the device’s permissions.
A law firm or financial business should first establish whether the identified versions were installed at all. An affected device requires technical investigation and an assessment of possible exposure of accessible documents, connections and authentication credentials.
The incident does not establish a data leak at any particular firm or business. It provides a reason to maintain an inventory of AI tools and extensions, recording the distribution channel, version, permissions and responsible owner.