Cursor says up to 5,000 users affected by tampered Claude Code extension

Space Exploration Technologies

30/10/2026 08:30

Oct 30 (Reuters) - Cursor, the coding-tool company owned by SpaceX SPCX.O, said on Friday that a maliciously modified version of Anthropic’s Claude Code extension was available on its Cursor VS Code extension marketplace on Thursday, affecting up to 5,000 users.
Here are some details:
Cursor said the extension was not developed by Anthropic and the maliciously modified extension was live on the marketplace from about 2:27 a.m. PT to 1:35 p.m. PT on Thursday
The extension attempted to collect host and user information such as hostname, username, operating system and public IP address
It also attempted to set up remote access for the attacker; Cursor said a key step would have failed on most machines because it requires administrator rights
Upon detection, Cursor removed the malicious version and blocked its distribution and shut down the marketplace as a precaution
The company then rebuilt the marketplace and brought it back online, it said
Cursor said the incident did not impact other extensions on its marketplace
Anthropic did not immediately respond to a request for comment
     

 (Reporting by Shubham Kalia in Bengaluru; Editing by Mrigank Dhaniwala)
 ((Shubham.Kalia@thomsonreuters.com))