Mini Shai-Hulud strikes again: TanStack, Mistral, OpenSearch npm packages compromised

Last Updated: 2026-05-12T17:22:17Z

What’s Happening

Around 170 NPM packages have been compromised by the same group executing other “Mini Shai-Hulud” attacks. The attack seems to have begun with TanStack, a popular web UI frontend framework, had its npm packages compromised Initial discovery by Step Security. The attack has moved over to PyPi as well.

TanStack has published their post-mortem here:

OpenSourceMalware has a breakdown of the current spread, now at 170 packages. These include the Mistral AI clients.

Actions

Review Socket’s very long list of compromised packages and search in your environment. It appears all affected packages share a new router_init.js file.

If these indicators are found, rotate all relevant secrets, session tokens, etc.

Indicators of Compromise

Value Type Description
ab4fcadaec49c03278063dd269ea5eef82d24f2124a8e15d7b90f2fa8601266c SHA256 Hash of router_init.js
router_init.js String Filename of common indicator file
filev2.getsession.org Domain Session C2 Domain
api.masscan.cloud Domain C2 Domain
git-tanstack.com Domain C2 Domain
bun run tanstack_runner.js Process Command Line Launches router_init.js

Notes

The relevant issue on their router package appears to be a good source of updates. They are working on an incident report now.

Socket has another writeup.

Looks like quite a few examples of the attack code have been published to GitHub:

3 Likes

The consistent use of Bun is interesting to me. I am not sure, but it would be useful if we could distinguish normal developer usage from attacker invocations.

2 Likes

So I looked into it and yes. The Bun dropper in Mini Shai-Hulud installs either to a /tmp directory via mktemp -d, or the repo parent directory. This is in contrast to the normal Bun install location. Detecting these process executions should be fairly high fidelity.

OpenAI had two employees impacted, and as a result are rotating code signing certs.

The impacted source code repositories included signing certificates for our products, including iOS, macOS, and Windows. As a result, we are rotating code-signing certificates as a precaution, which will require macOS users to update their applications. Users do not need to take any action for Windows and iOS apps. Additional guidance will be provided to macOS users regarding these required updates.

https://openai.com/index/our-response-to-the-tanstack-npm-supply-chain-attack/