# MAL-2026-13946: Malicious code in date-fmt-helper-xz (npm)


- **Type:** Malicious package
- **Package:** `date-fmt-helper-xz` (npm)
- **Published:** 13 Aug 2026

## What is MAL-2026-13946?

MAL-2026-13946 is a malicious package in date-fmt-helper-xz, published on 13 Aug 2026. 

### Official description

date-fmt-helper-xz ships a postinstall.js that runs automatically on npm install. The script opens a TCP connection to the hardcoded remote host 8.135.48.40 on port 4444 and pipes /bin/sh stdio over the socket, granting the remote party interactive shell access on the installer's machine. Bash /dev/tcp and python3 pty.spawn fallbacks are included to maximize the chance the shell succeeds across environments. On failure of the shell paths, the script issues an HTTP GET to http://8.135.48.40/shell/failed and /shell/error with the error message, confirming the same host as attacker command-and-control. The package advertises date formatting; the reverse shell is unrelated to any legitimate functionality.

## What should I do about MAL-2026-13946?

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-2026-13946 is a malicious package: date-fmt-helper-xz (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-2026-13946/ (Markdown: https://insights.sbomify.com/MAL-2026-13946/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-13946

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-13946/
Summaries are generated and may contain mistakes; the official description above is the record.