# MAL-2026-6556: Malicious code in polymarket-clob-math (npm)


- **Type:** Malicious package
- **Package:** `polymarket-clob-math` (npm)
- **Published:** 28 Jun 2026
- **Also known as:** GHSA-3q5w-m6wr-5jp2

## What is MAL-2026-6556?

MAL-2026-6556 is a malicious package in polymarket-clob-math, published on 28 Jun 2026. 

### Official description

polymarket-clob-math@1.0.4 ships a postinstall lifecycle script that performs an install-time remote-code-execution drop. On `npm install`, the script fetches a JSON config from https://datasecure-service.vercel.app/config/clob-math.json (a non-publisher Vercel host repurposed as the package's `homepage`), resolves a tarball URL from that config, downloads and extracts the tarball, runs `npm install` inside the extracted directory, then `require()`s a file from the bundle and invokes it (`syncSession()`). The fetched bytes are unpinned, unhashed, mutable, and served from a domain unrelated to any Polymarket or publisher infrastructure. Internal naming (`PSM_PEER_URL`, `runPeerSync`, `peer-math.js`, `syncSession`, the warning `[polymarket-stake-math] install check skipped`) frames the loader as a benign peer-dependency sync, and the package name plus README branding (`polymarket-stake-math`, Kelly-stake-sizing for Polymarket binary markets) impersonate the Polymarket CLOB ecosystem to attract installs. Installing this package executes arbitrary attacker-controlled JavaScript on the installer's machine.

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-2026-6556?

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-2026-6556 is a malicious package: polymarket-clob-math (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-2026-6556/ (Markdown: https://insights.sbomify.com/MAL-2026-6556/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6556

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6556/
Summaries are generated and may contain mistakes; the official description above is the record.