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Miasma Worm Hits 73 Microsoft GitHub Repositories in Major Supply Chain Attack

Thehackernews •[email protected] (The Hacker News) • June 6, 2026

Microsoft's GitHub repositories have become the latest to fall victim to the ongoing Miasma self-replicating supply chain attack campaign.

The incident impacted 73 Microsoft repositories across four of its GitHub organizations, including Azure, Azure-Samples, Microsoft, and MicrosoftDocs, per OpenSourceMalware. The development has GitHub to disable access to those repositories.

"Access to this

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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. 149 sources 68

Extracted Entities

Miasma Worm Hits 73 Microsoft GitHub Repositories in Major Supply Chain Attack

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Extracted Entities

Attack Types (1)

Companies (4)

Malware (2)

Platforms (1)