# MAL-2026-18054: Malicious code in @decoopus/claude-setup (npm)


- **Type:** Malicious package
- **Package:** `@decoopus/claude-setup` (npm)
- **Published:** 19 Oct 2026
- **Also known as:** GHSA-p7p5-jrq5-q47x

## What is MAL-2026-18054?

MAL-2026-18054 is a malicious package in @decoopus/claude-setup, published on 19 Oct 2026. 

### Official description

The npm package @decoopus/claude-setup@1.0.8 presents itself as an official Anthropic Claude Desktop setup CLI, using Anthropic branding, a 'Claude Max 20x · API Usage Billing' banner, and model identifiers that do not correspond to real Anthropic releases (claude-fable-5-1, claude-opus-5-5, claude-sonnet-5-5, claude-haiku-5-5). When run, the CLI writes a hardcoded gateway URL, https://api-anthropic.help, together with the user-supplied Anthropic API key into Claude Desktop's own configuration file, the Windows registry policy hive HKCU\SOFTWARE\Policies\Claude, and the macOS managed-preferences domain com.anthropic.claudefordesktop (fields inferenceGatewayBaseUrl and inferenceGatewayApiKey). After this reconfiguration, every prompt subsequently entered into Claude Desktop, along with the configured API key, is sent by the app to api-anthropic.help instead of Anthropic's own API. A clearCachedSession() routine additionally recursively deletes Session Storage, Local Storage, IndexedDB, Network, Partitions, GPUCache, and Code Cache subdirectories from the real Claude Desktop user data directories on Windows (including MSIX LocalCache), macOS, and Linux, forcing the official client to re-authenticate against the attacker gateway. The lookalike domain api-anthropic.help is not an Anthropic-owned endpoint; the combination of brand impersonation, non-existent model tiers, hardcoded redirection of another vendor's application traffic, and destruction of that application's session state constitutes exfiltration of the installer's API key and ongoing prompt contents to an attacker-controlled destination.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-18054?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-18054 is a malicious package: @decoopus/claude-setup (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-18054/ (Markdown: https://insights.sbomify.com/MAL-2026-18054/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-18054

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-18054/
Summaries are generated and may contain mistakes; the official description above is the record.