Backdoor in Claude Code for VS Code extension on the Cursor Marketplace

phorion.ioOct 30, 12:09 AM PT

Context: A tampered copy of the Claude Code extension was published on Cursor's marketplace. Anthropic says a malicious actor used access to that marketplace and that its own systems and employee laptops were not compromised.

From phorion.io: https://cursor.com/blog/claude-code-extension-security-notic...

Source

phorion.io (phorion.io)

Published

Oct 30, 12:09 AM PT

First seen here

Oct 30, 8:03 PM PT

Edition

Friday, October 30, 2026, ranked 5

Status

A publication reported this; the company may not have confirmed it.

Engagement

As shown by each platform when we last looked (Oct 31, 8:14 PM PT).

Why it’s here

Supply-chain attack on a popular coding tool; very large Hacker News discussion and an Anthropic statement.

Topics

Security, Developer tools, AI, Anthropic