Cursor removes malicious Claude Code 2.1.313 extension from its extension marketplace

Cursor confirmed that on October 29 its extension marketplace hosted a malicious Claude Code extension labeled 2.1.313, potentially affecting up to 5,000 users; it has now been removed and remediation guidance published. An earlier OpenSourceMalware analysis said the macOS version of the extension would add SSH authorized keys, attempt to establish a reverse SSH tunnel and install persistence, but the Open VSX channel it initially pointed to was refuted by Socket's verification: Socket checked 3,392 change events on Open VSX since October 27 and npm's publication records, and found no trace of 2.1.313 being published or taken down, and the Linux and Windows download sizes in the initial report's screenshots match the publicly available 2.1.314 version, so Socket suspects the screenshots were edited or made for illustration.