MAL-2026-3371 Malicious code in pycacheopt (PyPI)
Malicious package
Published
MAL-2026-3371 is a malicious package: pycacheopt (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-2026-3371/ (Markdown: https://insights.sbomify.com/MAL-2026-3371/index.md)
- Package
- pycacheopt
- Registry
- PyPI
What is MAL-2026-3371?
MAL-2026-3371 is a malicious package in pycacheopt, published on 7 May 2026.
Official description
The extension module hides code that in specific circumstances executes given code. The malicious action is hidden only in the extension module with the same-named Python code file containing only benign code.
This campaign was first detected by Aikido Security.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-05-pycacheopt
Reasons (based on the campaign):
other
The package contains code to detect if it is running in a sandbox environment.
What should I do about MAL-2026-3371?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.