Trojanized Claude Code Extension Planted an SSH Backdoor on Up to 5,000 Cursor Users
For about 11 hours on Thursday, October 29, Cursor’s extension marketplace served its users an update to Anthropic’s Claude Code extension that Anthropic didn’t write. Version 2.1.313 arrived under the extension’s real publisher ID, anthropic.claude-code, so anyone with auto-updates on could pick it up without clicking anything suspicious. Cursor says at most 5,000 users received the tampered build. That’s a small number next to Cursor’s user base. It’s a big deal anyway, because of where the package came from and what it tried to do. ...