Cursor removes a backdoored Claude Code extension from its marketplace
Cursor says a malicious Claude Code extension, version 2.1.313, affected at most 5,000 users on October 29. OpenSourceMalware independently inspected the injected SSH-backdoor code; the malicious package was distributed through Cursor's marketplace. Cursor removed the package and says the attacker's server is offline, though SSH activation failed on most macOS and Windows hosts without administrator rights.
ThereforeAffected developers need to remove persistent files and unauthorized SSH keys and rotate credentials; uninstalling the extension alone may not clean the host.
Cursor security notice · OpenSourceMalware analysis · The Hacker News