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Malware in markdownlint-cli2-fix

Malware was discovered in the npm package markdownlint-cli2-fix. Systems with this package installed or running should be considered fully compromised and require immediate remediation.

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Disclosed
Last updated
Blast radius
Any system with the package installed or running
Ecosystems
Attack vectors
Affected entities
  • markdownlint-cli2-fix

A malware incident was identified in the npm package markdownlint-cli2-fix. According to the GitHub Advisory (GHSA-75g7-vcxw-p99c), any computer that has this package installed or running should be considered fully compromised.\n\nThe advisory recommends that all secrets and keys stored on affected computers be rotated immediately from a different, uncompromised system. While the package should be removed, there is no guarantee that removal will eliminate all malicious software that may have been installed as a result of the package installation, given the potential for full system compromise.\n\nThis represents a critical supply chain attack through a compromised npm package with broad impact on any system where it was installed or executed.

Indicators of compromise

Packages
  • markdownlint-cli2-fix

Remediation

  • Immediately rotate all secrets and keys stored on affected computers from a different, uncompromised system
  • Remove the markdownlint-cli2-fix package from all affected systems
  • Conduct a full security audit and malware scan of any system that had this package installed or running
  • Review system logs and network traffic for signs of unauthorized access or data exfiltration
  • Consider the affected system(s) as potentially fully compromised and plan for complete rebuild if critical systems are involved

Sources

  1. GitHub Advisory GHSA-75g7-vcxw-p99c · GitHub Advisory Database

Cite this entry

"Malware in markdownlint-cli2-fix." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed June 24, 2026; last updated June 24, 2026. https://supplychainattack.org/incident/malware-in-markdownlint-cli2-fix-1bfzor

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