# MAL-2026-10990: Malicious code in ts-vitest (npm)


- **Type:** Malicious package
- **Package:** `ts-vitest` (npm)
- **Published:** 21 Jul 2026
- **Also known as:** GHSA-2g3m-3343-pgvq

## What is MAL-2026-10990?

MAL-2026-10990 is a malicious package in ts-vitest, published on 21 Jul 2026. 

### Official description

ts-vitest is a typosquat of vitest/ts-eslint (hollow "kelly-calc"/"clob-math" content, no legitimate functionality) that ships a postinstall two-stage fetch-exec dropper. The package.json declares `postinstall: node scripts/install-check.cjs`; the hook's `resolvePeerBundleUrl()` fetches a JSON config from a hardcoded, typosquatting host (`https://ts-eslint.vercel.app/config/clob-math.json`, also the package.json homepage), reads a second-stage tarball URL out of that config, npm installs the tarball, then `require()`s and executes it — achieving install-time RCE before any package code is used. The config JSON resolves to a second-stage tarball at `https://ts-eslint.vercel.app/releases/psm-peer.tgz`, whose `main` entry point is `peer-math.js`. The config indirection (an ephemeral *.vercel.app host serving JSON that points at the real payload) keeps the tarball URL out of the package bytes, defeating a naive grep for a hardcoded payload URL.

The lineage alternates malicious and clean releases: 1.1.1 shipped the dropper (previously convicted), 1.1.2 removed the postinstall hook as a clean decoy, and 1.1.3 restores a byte-identical copy of the 1.1.1 dropper. The hook is entirely YARA-invisible (0 matches); detection required reading the hook's logic directly rather than relying on signature scoring. Published by sole npm maintainer `naradi` (maintainer email `les.t.e.rbigs.antos@gmail.com`), who pushed 7 versions in ~6.5 hours.

The package is published as `ts-vitest` and its README advertises a TypeScript/Jest transformer, but the shipped code is unrelated (a Kelly-stake helper) and the postinstall hook performs install-time remote code execution. On `npm install`, the postinstall resolves a bundle URL from a JSON config at `https://ts-eslint.vercel.app/config/clob-math.json` (a lookalike of the legitimate `typescript-eslint` project), downloads the returned `.tgz` archive, extracts it, runs `npm install` inside the extracted directory, then `require`s `peer-math.js` and invokes `syncSession()` in the installer's Node process. There is no version pin, no hash or signature check, and the config host is author-controlled and mutable, so the executed payload can be changed at any time. The name/README cover story combined with the typosquat-style config domain is a deliberate dropper shape.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-10990?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-10990 is a malicious package: ts-vitest (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-10990/ (Markdown: https://insights.sbomify.com/MAL-2026-10990/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-10990

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-10990/
Summaries are generated and may contain mistakes; the official description above is the record.