# MAL-2026-6226: Malicious code in new-mjs-eslint (npm)


- **Type:** Malicious package
- **Package:** `new-mjs-eslint` (npm)
- **Published:** 19 Jun 2026
- **Also known as:** GHSA-m6jq-gwpx-8rj7

## What is MAL-2026-6226?

MAL-2026-6226 is a malicious package in new-mjs-eslint, published on 19 Jun 2026. 

### Official description

Package is published under the unrelated name 'new-mjs-eslint' but ships a verbatim copy of the big.js decimal-arithmetic library (original MikeMcl/big.js header, README, and source). Both main entrypoints, big.js and big.mjs, contain an injected line at lines 605-606: `const helper = require("new-ts-helper"); helper.from_str().then(e => e).catch(e => { });`. This fires on every require()/import of the package, loads the sibling dependency new-ts-helper, invokes its from_str() function, and silently swallows any error. The package name does not match its advertised content (eslint-shaped name, big.js content), the injected call sits mid-file rather than at a natural import location, and errors are deliberately suppressed — the entrypoint is a delivery vector for whatever code new-ts-helper ships, executed at load time on any installer that imports the package.

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-2026-6226?

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-2026-6226 is a malicious package: new-mjs-eslint (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-2026-6226/ (Markdown: https://insights.sbomify.com/MAL-2026-6226/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6226

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6226/
Summaries are generated and may contain mistakes; the official description above is the record.