Malicious Claude Code extension in Cursor's marketplace attempted remote access and data theft Matthias Bastian View the LinkedIn Profile of Matthias Bastian Oct 30, 2026 Heads up if you recently installed the Claude Code extension for Cursor. A tampered version was available in the Cursor VS Code extension marketplace on Thursday for about eleven hours, affecting up to 5,000 users, according to the company. Anthropic had no involvement in developing it. T