Malicious Package Affecting postmark-mcp package, versions >=1.0.16
Threat Intelligence
Snyk has reported that there have been attempts or successful attacks targeting this vulnerability.
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Test your applications- Snyk IDSNYK-JS-POSTMARKMCP-13052679
- published26 Sept 2025
- disclosed26 Sept 2025
- creditIdan Dardikman
Introduced: 26 Sep 2025
Malicious CVE NOT AVAILABLE CWE-506 (opens in a new tab)How to fix?
Avoid using all malicious instances of the postmark-mcp package.
Overview
postmark-mcp is a malicious package. This is an MCP (Model Context Protocol) server intended to let AI assistants send emails via Postmark and it was reportedly modified to secretly exfiltrate email contents by adding a blind-copy (BCC) to an external domain.
Note:
If you have installed or used this package since mid-September 2025, assume exposure: uninstall it, rotate any credentials ever sent through it, and review email logs for BCC traffic to the reported domain.