A malicious Claude Code extension has appeared in the Cursor extension marketplace, affecting approximately 5,000 users.

Cursor stated on its X platform that a maliciously modified version of the Claude Code extension, version 2.1.313, appeared in its extension marketplace. This version was not developed by Anthropic and affected approximately 5,000 users. This malicious extension collects user host information and attempts to implant an SSH backdoor. Cursor has removed the extension and recommends that users update the Claude Code extension to version 2.1.314.