#npm

A copy of Postmark's MCP server, published to npm by someone unaffiliated with them, worked perfectly for fifteen versions. The sixteenth added one line — a BCC to an address the publisher controlled.

The malicious release carried valid SLSA provenance and passed every integrity check, because the honest build pipeline compiled source that was already poisoned. It also ran when a developer merely opened the folder.

A stranger emailed an unpaid maintainer offering to take over a package he no longer used. Three months later it was stealing private keys from bitcoin wallets holding more than 100 BTC. Nobody was ever identified.

Between late 2025 and mid-2026, the software supply chain threat landscape underwent a fundamental paradigm shift with the emergence of the Shai-Hulud malware lineage. Culminating in the highly...