North Korean Hackers Hijacked 140+ Mastra Packages in a Single npm Takeover

On June 17, 2026, attackers used a stolen maintainer token to republish more than 140 packages under the @mastra scope on npm. Mastra is an AI agent framework, and every republished package carried a malicious dependency built to harvest crypto wallets from anyone who installed it.

Microsoft's threat intelligence team attributed the operation to Sapphire Sleet, also tracked as BlueNoroff or APT38, a North Korea-linked group with a long history of financially motivated attacks against crypto infrastructure. According to Tech Insider's reporting, this marks the first confirmed case of a nation-state actor running a mass npm supply-chain operation at this scale, more than 140 packages compromised through a single stolen credential.

A single maintainer token, once stolen, was enough to reach every developer who had @mastra packages in their dependency tree, whether they were actively updating or just running a routine install. That's the structural risk in any package ecosystem built on maintainer trust: one compromised credential propagates to everyone downstream, instantly and without any additional action from the attacker.

If you or your team have Mastra packages anywhere in a dependency tree, checking install history against June 17, 2026 and rotating any crypto wallet credentials that touched an affected machine is the immediate step. The broader signal, a nation-state group running supply-chain attacks through ordinary npm maintainer accounts, is worth factoring into how much trust any single package maintainer's credentials deserve going forward.