# Claude Code extension backdoor persists despite flaw in macOS access setup

_Published Friday, October 30, 2026 at 10:55 AM EDT · Security · Latest · Tier 2 — Notable_

![Claude Code extension backdoor persists despite flaw in macOS access setup — Primary](https://phorion.io/images/default-social-card.png)

A backdoored Claude Code extension can leave persistent access mechanisms behind after removal, security firm Phorion reported in an analysis of version 2.1.313 on the Cursor Marketplace. Its injected code runs when the extension loads, plants an SSH authentication key and creates a reverse tunnel intended to give an attacker interactive access.

Phorion found that a faulty permissions check prevents the malware from enabling Remote Login on a standard-user Mac. That blocks the access path when SSH is off, but planted keys and persistence remain, and access can work if SSH is already enabled or enabled later. Uninstalling the extension alone does not remove those components.

## Sources

- [phorion.io](https://phorion.io/blog/offical-claude-code-vsx-compromise/)

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Canonical: https://techandbusiness.org/newswire/QW5jVVTrjbrOm2f_s3I82b
Published: 2026-10-30T14:55:15.731Z
Story chronology: 2026-10-30T00:00:00.000Z
Retrieved: 2026-10-30T17:43:39.725Z
Publisher: Tech & Business (techandbusiness.org)