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resolvedcritical

Malicious code in zlib1g-dev (PyPI)

Malicious code was discovered in the zlib1g-dev package on PyPI. The package was identified by the OpenSSF malicious packages project as containing malicious code.

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Disclosed
Last updated
Blast radius
Unknown scope; PyPI distribution
Ecosystems
PyPI
Attack vectors
Compromised package
Affected entities
  • zlib1g-devPyPI package

The zlib1g-dev package published on PyPI was found to contain malicious code. This incident was identified and documented by the OpenSSF's malicious packages project, which maintains a catalog of known malicious packages across package ecosystems.\n\nThe package appears to be a typosquatting or impersonation attempt, as zlib is a legitimate compression library typically distributed through system package managers (e.g., apt for Debian/Ubuntu) rather than PyPI. The presence of malicious code in this PyPI package represents a supply chain compromise targeting developers who may have mistakenly installed it.\n\nThe incident was disclosed on 2026-07-21 via GitHub Security Advisory GHSA-8vrj-mmvq-hp7r.

Indicators of compromise

Packages
  • zlib1g-dev

Remediation

  • Remove zlib1g-dev from PyPI if not already done
  • Audit systems and environments where zlib1g-dev was installed
  • Review package dependencies and lock files for presence of zlib1g-dev
  • Use legitimate zlib packages from official sources (system package managers or verified PyPI packages)
  • Monitor for indicators of compromise from systems that may have installed the malicious package

Sources

  1. GitHub Advisory GHSA-8vrj-mmvq-hp7r · GitHub Advisory Database

Cite this entry

"Malicious code in zlib1g-dev (PyPI)." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed July 21, 2026; last updated July 21, 2026. https://supplychainattack.org/incident/malicious-code-in-zlib1g-dev-pypi-z571s5

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