# MAL-2026-6420: Malicious code in leo-cdk-lib (npm)


- **Type:** Malicious package
- **Package:** `leo-cdk-lib` (npm)
- **Published:** 24 Jun 2026

## What is MAL-2026-6420?

MAL-2026-6420 is a malicious package in leo-cdk-lib, published on 24 Jun 2026. 

### Official description

The `leo-cdk-lib` npm package was compromised as part of the Miasma worm campaign targeting the LeoPlatform npm ecosystem. On June 24, 2026, 20 LeoPlatform packages were published within a 3-second window by a threat actor who had taken over the npm account `czirker` belonging to the LeoPlatform organization.

The malicious payload is triggered automatically during `npm install` via a `binding.gyp` file using node-gyp command expansion (`<!(node index.js > /dev/null 2>&1 && echo stub.c)`), which bypasses lifecycle script scanners. The replaced `index.js` (~5.2 MB, obfuscated with ROT-N + AES-128-GCM encryption) deploys a multi-stage worm with the following capabilities:

- Credential theft: Targets npm, GitHub, PyPI, RubyGems, Kubernetes, HashiCorp Vault, AWS (IAM keys, Secrets Manager, IMDS), 1Password, JFrog Artifactory, and SSH keys.
- AI tool targeting: Exfiltrates configuration files for Claude, Cursor, Gemini, and VS Code.
- Worm propagation: Enumerates npm packages and auto-publishes version bumps to spread to other maintainers in the ecosystem.
- GitHub persistence: Creates orphan `snapshot-<hex>` branches with fake "Dependabot Updates" workflows to maintain access after initial compromise.

Any system that installed this version should be considered fully compromised. Rotate all secrets immediately from a separate, clean machine. See the linked SafeDep report for full payload analysis, indicators of compromise, and remediation guidance.

The package ships a binding.gyp at the root that contains GYP command-expansion syntax (<!(...)) inside the targets/sources fields. npm implicitly runs node-gyp rebuild whenever a binding.gyp is present, even without a declared install/postinstall script, and GYP evaluates <!(...) as a shell command during the configure step. This causes the embedded command to execute automatically on `npm install`, functionally equivalent to a lifecycle hook. The package does not ship corresponding native source files (.c/.cc/.cpp/.h) that would justify a real node-gyp build, indicating the binding.gyp's purpose is to run the embedded command rather than to build a native addon.

## What should I do about MAL-2026-6420?

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-2026-6420 is a malicious package: leo-cdk-lib (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-2026-6420/ (Markdown: https://insights.sbomify.com/MAL-2026-6420/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6420

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6420/
Summaries are generated and may contain mistakes; the official description above is the record.