“An extension marketplace is effectively another software supply chain,” Kadakia said. “When malicious code can reach developers through what appears to be a legitimate, routine update, the traditional assumption that software from a trusted marketplace is safe starts to break down.”
He recommended stronger publisher verification, checks on package integrity, and controls over which extensions and versions developers can install.
Kadakia also called for extension allowlisting, controlled updates, endpoint monitoring, and restrictions on outbound connections. He said short-lived credentials, segregated development environments, and limited access to sensitive infrastructure could reduce the impact of a compromised developer machine. Cursor said it removed the malicious versions, temporarily shut down its marketplace, audited access, rotated keys, and rebuilt the marketplace before restoring the service.
