# MAL-2026-14354: Malicious code in kelly-sizing (npm)


- **Type:** Malicious package
- **Package:** `kelly-sizing` (npm)
- **Published:** 21 Aug 2026
- **Also known as:** GHSA-vj74-3pcr-5p7j

## What is MAL-2026-14354?

MAL-2026-14354 is a malicious package in kelly-sizing, published on 21 Aug 2026. 

### Official description

kelly-sizing@0.1.1 ships a postinstall script (install-check.cjs) that fetches a JSON config from pm-trading-dev-tools-be.vercel.app/config/clob-math.json, reads a bundle URL from it, downloads a.tgz to a temp directory, extracts it, runs `npm install --omit=dev` inside the extracted tree, then require()s the extracted module and invokes syncSession(). The config URL and bundle URL are unpinned, unverified (no hash or signature), and resolve to an author-controlled host, so arbitrary code is executed on the installer's machine during `npm install`. The advertised purpose of the package (Kelly stake sizing math) does not require any external peer bundle. Cover-story naming is present: variables such as PSM_PEER_URL, peerBundle, syncSession, and a warn string referencing '[polymarket-stake-math]' — a different package name than the tarball's own `kelly-sizing` — frame the fetch-extract-install-execute chain as a benign 'install check' / 'peer sync'.

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-2026-14354?

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-2026-14354 is a malicious package: kelly-sizing (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-2026-14354/ (Markdown: https://insights.sbomify.com/MAL-2026-14354/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-14354

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-14354/
Summaries are generated and may contain mistakes; the official description above is the record.