# MAL-2026-5876: Malicious code in temp-development-package-test (PyPI)


- **Type:** Malicious package
- **Package:** `temp-development-package-test` (PyPI)
- **Published:** 16 Jun 2026

## What is MAL-2026-5876?

MAL-2026-5876 is a malicious package in temp-development-package-test, published on 16 Jun 2026. 

### Official description

At install time, setup.py invokes install_sitecustomize(), which copies src/temp_development_package_test/setup/sitecustomize.py into Python's purelib site-packages directory as sitecustomize.py (setup.py:34 destination = site_packages / "sitecustomize.py"; setup.py:36 shutil.copy2(source, destination)). Python auto-imports sitecustomize on every interpreter startup, so this places an interpreter-wide hook outside the package's own namespace that fires for every subsequent Python process on the host — a classic persistence mechanism. The hook payload file is not actually shipped in this 0.2 sdist, so the install would currently raise FileNotFoundError, but the install-time mechanism and intent to write a global hook are unambiguous. The package metadata corroborates a throwaway / probe release: name, author, and summary are all the literal placeholder 'temp_development_package_test'; setup.py imports base64 but never uses it; cli.py imports from an unrelated, undeclared module 'pg_agent.orchestration.coordinator'. The combination — placeholder identity plus install-time write of a global interpreter hook — is not a legitimate package shape.

Starting with version 0.4, package installs a sitecustomize.py that executes during Python engine initialization. The embeded code uses mshta to download malicious code, as in other packages from the campaign.

---

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

Campaign: 2026-06-easyaillm

Reasons (based on the campaign):

 - Downloads and executes a remote executable.

 - obfuscation

 - malware

 - tool:mshta

## What should I do about MAL-2026-5876?

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-2026-5876 is a malicious package: temp-development-package-test (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-2026-5876/ (Markdown: https://insights.sbomify.com/MAL-2026-5876/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5876

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5876/
Summaries are generated and may contain mistakes; the official description above is the record.