Malicious Claude Code versions hit the Cursor extension marketplace: check now if you installed 2.1.312 or 2.1.313 on Oct 29
Cursor issued a security notice: between about 2:27am and 1:35pm PT on October 29, tampered versions 2.1.312 and 2.1.313 of Anthropic's Claude Code extension for Windows and macOS were available in its VS Code extension marketplace, trying to plant an SSH backdoor and send out host details. Cursor pulled them, rebuilt the marketplace and published check and cleanup scripts. My take: AI coding tools run with your computer's full permissions, so installing an extension is like handing over your house keys. Companies need an approved-extensions list, and anyone who installed during that window should follow the official steps and rotate passwords and keys.