Megalodon Malware Compromised 5,500+ GitHub Repos Within 6 Hours

Cybersecuritynews •Guru Baran • May 22, 2026

A sweeping automated supply chain attack codenamed “Megalodon” struck GitHub on May 18, 2026, injecting malicious CI/CD backdoors into over 5,500 repositories in less than six hours, marking one of the most aggressive GitHub Actions poisoning campaigns ever recorded. SafeDep discovered that between approximately 11:36 and 17:48 UTC on May 18, 2026, the Megalodon campaign […]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

GitHub Breach: 3,800 Internal Repositories Compromised via Malicious VS Code Extension On May 20, 2026, GitHub confirmed a significant security breach involving a poisoned Visual Studio Code (VS Code) extension that compromised an employee's device. The attack, attributed to the TeamPCP hacking group, resulted in the exfiltration of approximately 3,800 internal repositories. GitHub's initial assessment indicated that the breach did not affect customer data stored outside its internal systems. The malicious extension was promptly removed, and GitHub initiated an incident response, including credential rotation. TeamPCP is reportedly offering the stolen data for sale on cybercrime forums, demanding at least $50,000. The breach highlights vulnerabilities in developer tools and the potential for significant impacts on software supply chains. GitHub is continuing to monitor for any follow-on activity as the investigation progresses. 111 sources 68

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Megalodon Malware Compromised 5,500+ GitHub Repos Within 6 Hours

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