Which versions of polymarket-clob-client are malicious?

The following npm versions of polymarket-clob-client are flagged malicious: 2.1.1. Treat any of these as compromised.

How do I remediate polymarket-clob-client if I installed it?

polymarket-clob-client is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

I already installed polymarket-clob-client — how do I know if it already compromised me?

If polymarket-clob-client was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Is polymarket-clob-client part of a known attack campaign?

Yes — polymarket-clob-client is associated with the IN-MAL-2026-003357 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find polymarket-clob-client across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for polymarket-clob-client (version 2.1.1).

Malicious package

polymarket-clob-clientnpm

Advisory published May 20, 2026Updated May 26, 2026

polymarket-clob-client is a confirmed malicious npm package (MAL-2026-4643) that steals credentials and exfiltrates sensitive data (malicious version 2.1.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in polymarket-clob-client (npm)

MAL-2026-4643

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall polymarket-clob-client

What this malware does

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.

Malicious versions

1 flagged

2.1.1

Indicators of compromise (SHA-256)

7e0a3a7bbeb25fb478d59cdd4b62ebb34c13e8e236505813660e81abf61e74ec

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for polymarket-clob-client (version 2.1.1).
If you installed it — respond
polymarket-clob-client is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If polymarket-clob-client was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. polymarket-clob-client on npm has been identified as a malicious package (version 2.1.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-003357

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks polymarket-clob-client-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database