# MAL-2026-13978: Malicious code in datefmt-util-helper (npm)


- **Type:** Malicious package
- **Package:** `datefmt-util-helper` (npm)
- **Published:** 13 Aug 2026

## What is MAL-2026-13978?

MAL-2026-13978 is a malicious package in datefmt-util-helper, published on 13 Aug 2026. 

### Official description

Package presents itself as a date-formatting utility but ships a postinstall reverse shell. package.json declares scripts.postinstall = 'node postinstall.js'; postinstall.js hardcodes VPS = '8.135.48.40' and PORT = 4444 and runs execSync of a python3 -c payload that opens a socket to that host and invokes pty.spawn('/bin/bash'), with fallback branches using python3 subprocess and a Node net + child_process.spawn('/bin/bash') chain. Runs automatically during `npm install`, giving the remote host full interactive shell control on the installer's machine as the installing user. index.js implements a trivial date formatter as cover (a source comment translates to 'disguised as a normal date-formatting tool'); the library surface exists only to legitimize the package.

## What should I do about MAL-2026-13978?

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-2026-13978 is a malicious package: datefmt-util-helper (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-2026-13978/ (Markdown: https://insights.sbomify.com/MAL-2026-13978/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-13978

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-13978/
Summaries are generated and may contain mistakes; the official description above is the record.