Felix Rieseberg / @felixrieseberg : Anthropic says a malicious actor used access to Cursor's marketplace to publish a “tampered” copy of the Claude Code extension, which it didn't build or publish — We're working with Cursor on this incident, but it wasn't a compromise of Anthropic's systems or employee laptops. A malicious actor used access to Cursor's marketplace to publish a tampered copy of the Claude Code extension, which we didn't build or publish. The versions on our official channels a...
Anthropic says a malicious actor used access to Cursor's marketplace to publish a "tampered" copy of the Claude Code extension, which it didn't build or publish (Felix Rieseberg/@felixrieseberg)
In short
A tampered version of the Claude Code extension was published to Cursor's marketplace by a malicious actor without Anthropic's involvement. Anthropic confirmed that its own internal systems and staff laptops remained uncompromised throughout the event. In response, the organization is actively working alongside Cursor to remediate the unauthorized release. Users can continue to safely access legitimate copies distributed through Anthropic's verified distribution channels.
Key points
- Anthropic is coordinating directly with the Cursor team to remediate the unauthorized sof…: Anthropic is coordinating directly with the Cursor team to remediate the unauthorized software publication.
- The altered developer extension was neither built nor published by Anthropic's authorized…: The altered developer extension was neither built nor published by Anthropic's authorized engineering team.
- Developers should download the Claude Code extension solely through Anthropic's verified…: Developers should download the Claude Code extension solely through Anthropic's verified channels for security.