# MAL-2026-3759: Malicious code in env-threads (npm)


- **Type:** Malicious package
- **Package:** `env-threads` (npm)
- **Published:** 14 May 2026

## What is MAL-2026-3759?

MAL-2026-3759 is a malicious package in env-threads, published on 14 May 2026. 

### Official description

Package `env-threads` impersonates the legitimate `dotenv` package: its README, repository URL (`git://github.com/motdotla/dotenv.git`), homepage, description, keywords (`dotenv`, `env`, `.env`, `environment`, `variables`, `config`, `settings`), and public API surface (`config`, `parse`, `populate`) are copied from dotenv, but the package name differs. Unlike genuine dotenv — a small unobfuscated pure-JS parser — this package ships an 82 KB heavily obfuscated `lib/main.js` with hex-named identifiers and a string-array decoder (`xIuLO2(0x...)`). At module top level, the last executable statement runs `SbEjWpp(path.join(__dirname, <decoded-filename>))`, which resolves to `lib/stest.jpg`. The `SbEjWpp` function calls `fs.readFileSync` on that file and extracts an embedded payload via steganographic decoding, then executes it through `child_process`. Every consumer who adds `env-threads` to their dependency tree and requires it — typically expecting dotenv-like behavior — triggers arbitrary code execution from a payload hidden inside a JPEG shipped in the tarball. The combination of (1) verbatim typosquat of a top-tier npm package, (2) heavy obfuscation absent from the impersonated original, and (3) child_process execution of steganographically-hidden bytes at require-time is unambiguous supply-chain malware.

## What should I do about MAL-2026-3759?

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-2026-3759 is a malicious package: env-threads (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-2026-3759/ (Markdown: https://insights.sbomify.com/MAL-2026-3759/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-3759

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-3759/
Summaries are generated and may contain mistakes; the official description above is the record.