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Postmark-mcp npm backdoor copying outbound emails

Malware Activity
First reported
Last updated
Happening score
H score 28
1 unique sources, 1 articles

Summary

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The postmark-mcp npm package was found to include a backdoor that silently copied outbound emails, creating a supply-chain risk for users of the MCP server. The malicious code appeared in version 1.0.16 and forwarded messages to phan@giftshop[.]club. The package was later removed from npm after discovery. Anyone who installed it may have exposed sensitive mail content handled by the server.

Related Happenings

Shai-Hulud worm clone activity on NPM

Malware Activity
H score69 First: 18.05.2026 12:45 Last: 18.05.2026 12:45 Sources 1

About this happening: The Shai-Hulud malware activity has continued to evolve across the npm supply chain and related developer ecosystems. It first infected npm packages in September 202...

Open Happening

Inactive maintainer account 'atiertant' hit by network compromise

Incident
H score13 First: 15.05.2026 20:10 Last: 15.05.2026 20:10 Sources 1

About this happening: The inactive maintainer account 'atiertant' for node-ipc was compromised, enabling malicious package releases that could steal credentials from downstream installation...

Open Happening

Shai-Hulud supply-chain campaign spreading via stolen CI/CD credentials

Campaign
H score56 First: 12.05.2026 14:29 Last: 12.05.2026 14:29 Sources 1

About this happening: GitHub said it removed more than 500 compromised npm packages in September 2025 and moved to harden publishing after early Shai-Hulud activity. In May 2026, researcher...

Open Happening

Mini Shai-Hulud npm supply-chain malware wave

Malware Activity
H score68 First: 12.05.2026 14:07 Last: 12.05.2026 14:07 Sources 1

About this happening: The Mini Shai-Hulud npm malware activity now includes the Miasma variant affecting Microsoft GitHub repositories in a self-replicating supply-chain campaign. O...

Latest development: 09.06.2026 18:42

On June 5, Microsoft removed 73 repositories across its Azure, microsoft, Azure-Samples, and MicrosoftDocs organizations on GitHub after concerns about potential malicious content tied to the Miasma/Shai-Hulud supply-chain campaign. The action disrupted continuous integration pipelines and broke workflows that depended on Azure/functions-action, while Microsoft said it temporarily removed some repositories during its investigation.

Open Happening

Mini Shai-Hulud SAP-related npm supply-chain campaign

Campaign
H score45 First: 29.04.2026 19:26 Last: 29.04.2026 19:26 Sources 1

About this happening: A new Mini Shai-Hulud supply-chain campaign is targeting SAP-related npm packages, putting developer and CI/CD environments at risk of credential theft and malicious p...

Latest development: 12.05.2026 11:50

Mini Shai-Hulud expands beyond the original SAP-related npm packages to compromise TanStack, UiPath, Mistral AI, OpenSearch, Guardrails AI, and DraftLab packages across npm and PyPI, with malicious payloads using router_init.js, GitHub Actions abuse, and exfiltration to filev2.getsession[.]org, api.masscan[.]cloud, or attacker-controlled GitHub repositories.

Open Happening

Timeline

  3. 29.09.2025 11:36 2 articles · 9mo ago

    Koi Security identifies the malicious MCP server

    Initial Disclosure

    Koi Security identified postmark-mcp as the first real-world malicious MCP server and warned that it had been silently copying every outbound email to phan@giftshop[.]club, exposing sensitive communications and prompting users to remove the package and review BCC traffic.

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