# MAL-2026-18343: Malicious code in numprint (PyPI)


- **Type:** Malicious package
- **Package:** `numprint` (PyPI)
- **Published:** 27 Oct 2026

## What is MAL-2026-18343?

MAL-2026-18343 is a malicious package in numprint, published on 27 Oct 2026. 

### Official description

numprint 1.2.0 on PyPI could not be fully characterized from the available signals. No specific installer-harm fingerprint (hardcoded C2, credential path read, home-directory secret scan, install-time fetch-and-execute, dropper, backdoor, self-propagation) is concretely identified in this record. The package name resembles common numeric/printing utility names but no benign purpose is confirmed either.

During installation the package starts a background process executing commands provided by the attacker. The C2 communication happens through a GitHub Gist.

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Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2026-10-numprint

Reasons (based on the campaign):

 - The package overrides the install command in setup.py to execute malicious code during installation.

 - The package contains code to execute remote commands (probably limited to a specific set) on the victim's machine.

 - rat

## What should I do about MAL-2026-18343?

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-2026-18343 is a malicious package: numprint (PyPI). 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-2026-18343/ (Markdown: https://insights.sbomify.com/MAL-2026-18343/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-18343

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-18343/
Summaries are generated and may contain mistakes; the official description above is the record.