Malicious Claude Code extension in Cursor's marketplace attempted remote access and data theft
A tampered Claude Code extension was live on the Cursor marketplace for about 11 hours, affecting up to 5,000 users. It tried to steal user data and set up remote access. Cursor took the entire marketplace offline and reinstated it after confirming there was no further risk. The article Malicious C
Heads up if you recently installed the Claude Code extension for Cursor. A tampered version was available in the Cursor VS Code extension marketplace on Thursday for about eleven hours, affecting up to 5,000 users, according to the company. Anthropic had no involvement in developing it.
The extension tried to harvest user data like hostname, username, operating system, and public IP address. It also attempted to set up remote access for the attacker, though that likely wouldn't have worked on most machines since it requires admin privileges, Cursor says. Once discovered, Cursor pulled the extension and took the entire marketplace offline. After working with providers to neutralize the malware and confirming there was no further risk, the marketplace was reinstated. Cursor says no other extensions were affected.
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