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OpenAdvisories
Malicious MAL-2026-864

marshmellow

PyPI package · versions 1.0.0, 1.1.0

Reported Feb 12, 2026 · Updated Feb 19, 2026

If this package is installed

Remove it, treat the machine (or CI runner) as compromised, and rotate every secret, token and key it could access — from a different, clean machine.

Details

Source: kam193 (dbf6f50353e6489a831a2575831b93fd5f99a9cbd60cc30260fd13838beda73f)
Package is a typosquatting or dependency confusion attempt with a low-harm local-only action, like leaving a flag file.

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Category: PROBABLY_PENTEST - Packages looking like typical pentest packages, but also anything that looks like testing, exploring pre-prepared kits, research & co, with clearly low-harm possibilities.

Campaign: GENERIC-local-typosquatting

Reasons (based on the campaign):

- dependency-confusion

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

- typosquatting

Source: ossf-package-analysis (385a79bb53771282b64601f5a3b17f0d7a3d735efbf863584f0dd2755bc2bf08)
The OpenSSF Package Analysis project identified 'marshmellow' @ 1.1.0 (pypi) as malicious.

It is considered malicious because:

- The package executes one or more commands associated with malicious behavior.