# MAL-2026-6691: Malicious code in polymarket-clob-maths (npm)


- **Type:** Malicious package
- **Package:** `polymarket-clob-maths` (npm)
- **Published:** 30 Jun 2026

## What is MAL-2026-6691?

MAL-2026-6691 is a malicious package in polymarket-clob-maths, published on 30 Jun 2026. 

### Official description

Malicious npm package published as part of a coordinated DeFi-themed infostealer campaign targeting Polymarket developers. `polymarket-clob-maths` uses a dropper technique: a `postinstall` hook fetches a remote bundle from `trabalhos-flax.vercel.app` and executes a `syncSession()` function that runs a second-stage infostealer. The payload harvests cryptocurrency wallet vaults, browser credentials, SSH keys, AWS credentials, developer secrets, and password manager databases, then exfiltrates the data to the attacker-controlled C2.

On npm install, the declared postinstall hook (node scripts/install-check.cjs) fetches a JSON config from https://trabalhos-flax.vercel.app/config/clob-math.json, parses a bundle URL from the response, downloads a tgz to a temp directory, extracts it, runs `npm install` inside the extracted directory, then require()s peer-math.js from that bundle and invokes syncSession(). The fetched archive is unpinned, has no integrity check (no hash, no signature), and is hosted on a third-party Vercel app unrelated to Polymarket. The attacker fully controls the executed code on each install, and can change it at any time without republishing the npm package. The package additionally impersonates the Polymarket / @polymarket CLOB ecosystem: the published name is `polymarket-clob-maths` while the README is titled `polymarket-stake-math` and instructs users to `npm install polymarket-stake-math`, indicating namespace confusion against the legitimate Polymarket tooling. Cover-story naming (PSM_PEER_URL, KELLY_PEER_CONFIG, log strings calling the operation an `install check` / `peer sync`) and silenced errors (`console.warn('[polymarket-stake-math] install check skipped:', msg)`) hide the dropper behavior from a casual installer.

## What should I do about MAL-2026-6691?

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-2026-6691 is a malicious package: polymarket-clob-maths (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-2026-6691/ (Markdown: https://insights.sbomify.com/MAL-2026-6691/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6691

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6691/
Summaries are generated and may contain mistakes; the official description above is the record.