Cursor Warns of Malicious Packages in Claude Code Extension

The Cursor code editor has issued a security alert for developers who installed compromised versions of the Claude Code extension. Versions 2.1.312 and 2.1.313 were available on the marketplace between the early hours and the afternoon of October 29, 2026. The company clarifies that Anthropic did not develop these malicious packages.

Removing the extension does not guarantee the elimination of persistent components installed on the machine. The malicious code attempts to add attacker-controlled SSH keys and establish reverse tunnels for remote access. The attack occurs the moment Node loads the extension module.

Researchers identified that the malware creates persistence mechanisms through LaunchAgents on macOS and scheduled tasks on Windows. The system reports computer information and environment variable names to external servers. Cursor removed the packages and rotated its own security keys following the incident.

The official recommendation is to perform a complete system wipe on affected machines and immediately rotate all credentials and active sessions. Using a trusted system is essential to ensure that new keys are not intercepted. The hosting provider used by the attacker was shut down in collaboration with the editor.

Security incidents in development tools increase the risk of compromising private keys and digital wallets stored on programmers' machines. The integrity of the workspace directly influences trust in the digital asset ecosystem and the security of global transactions.