# MAL-2026-4643: Malicious code in polymarket-clob-client (npm)


- **Type:** Malicious package
- **Package:** `polymarket-clob-client` (npm)
- **Published:** 20 May 2026

## What is MAL-2026-4643?

MAL-2026-4643 is a malicious package in polymarket-clob-client, published on 20 May 2026. 

### Official description

The package is published as `polymarket-clob-client`, an unscoped lookalike of the legitimate `@polymarket/clob-client` maintained by Polymarket, but the shipped code is the third-party Hyperliquid SDK targeting a completely different exchange. `package.json` declares `"description": "Hyperliquid API SDK for all major JS runtimes..."` and the homepage points at `github.com/nktkas/hyperliquid`. The HTTP transport in `script/transport/http/mod.js` hardcodes `https://api.hyperliquid.xyz` as the default mainnet endpoint (`exports.MAINNET_API_URL = "https://api.hyperliquid.xyz"`). A developer who installs this package believing they are integrating with Polymarket's CLOB will instead be signing wallet messages and submitting trading orders to Hyperliquid. The structural signals — a clear name-squat of a well-known DeFi brand combined with code that silently routes wallet signatures and order intent to an unrelated venue — present concrete installer harm: misdirected funds and trading actions, regardless of whether the misnaming is intentional or negligent.

## What should I do about MAL-2026-4643?

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-2026-4643 is a malicious package: polymarket-clob-client (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-2026-4643/ (Markdown: https://insights.sbomify.com/MAL-2026-4643/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4643

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-4643/
Summaries are generated and may contain mistakes; the official description above is the record.