Cursor's latest security notice names two tampered Claude Code add-on versions for Windows and Mac. It warns that deleting the add-on may leave malicious scripts behind.
The warning covers versions 2.1.312 and 2.1.313 from Cursor's VS Code extension store. It applies to installs or updates between about 2:27 a.m. and 1:35 p.m. Pacific time on October 29. Cursor clarified the versions on October 30.
The packages tried to open a hidden route into the computer and sent user and machine details to an attacker. Cursor says the remote-login attempt failed on most Windows and Mac computers. A bug meant it needed admin rights, which Cursor would not usually have.
An attacker's remote-login key and scripts could still be left behind. Cursor's notice includes cleanup steps and says some computers may need to be rebuilt.
The company says it removed the packages, rebuilt its store and took the attacker's server offline. It says the malicious packages were not made by Anthropic. It has found no evidence that other versions or the official distribution were affected.