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Malicious package

@zahlen/checkoutnpm

Advisory published Updated

@zahlen/checkout is a confirmed malicious npm package (MAL-2026-13391) that steals credentials and exfiltrates sensitive data (malicious version 0.2.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @zahlen/checkout (npm)

MAL-2026-13391
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall @zahlen/checkout

What this malware does

No a static rule or traced code paths flagged malicious behavior in this package. No lifecycle hooks fetching or executing remote content, no credential or environment scraping, no hardcoded exfiltration endpoints, no silent-relay of caller data, and no persistence mechanisms were observed.

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.

Malicious versions

1 flagged
0.2.2

Indicators of compromise (SHA-256)

608af2e8bd10840c8019a74eef4f73478711e74c777f452ee03097500fc68222
4d1a20d08b428711d9b8c349d981cf4997f086b8cbd8dce407ef26e02706f33e

Detection & response playbook

Credential / info stealer
  1. Find it

    Search your lockfiles and build artifacts for @zahlen/checkout (version 0.2.2).

  2. If you installed it — respond

    @zahlen/checkout 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.

  3. Did it already run?

    If @zahlen/checkout 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. @zahlen/checkout on npm has been identified as a malicious package (version 0.2.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-vj9r-9wwp-6cfpIN-MAL-2026-016003

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks @zahlen/checkout-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Explore

@zahlen/checkout (npm) malicious package — MAL-2026-13391 | O3 Security