Which versions of 4xperss are malicious?

The following npm versions of 4xperss are flagged malicious: 1.0.0. Treat any of these as compromised.

How do I remediate 4xperss if I installed it?

Remove 4xperss from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed 4xperss — how do I know if it already compromised me?

If 4xperss 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.

How do I find 4xperss across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for 4xperss (version 1.0.0).

Malicious package

4xperssnpm

Advisory published Apr 2, 2026Updated Apr 7, 2026

4xperss is a confirmed malicious npm package (MAL-2026-2435) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in 4xperss (npm)

MAL-2026-2435

Immediate action

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

npm uninstall 4xperss

What this malware does

The package 4xperss was found to contain malicious code.

The OpenSSF Package Analysis project identified '4xperss' @ 1.0.0 (npm) as malicious.

It is considered malicious because:

The package executes one or more commands associated with malicious behavior.

Malicious versions

1 flagged

1.0.0

Indicators of compromise (SHA-256)

d8cb27dbe58e29571ce6b777903222af9497b79676e8301021d03f159c5d77ae

6de1a8af1dbe21de2e06785a6a5e41a438f356fe440c8b121b808975ef95f5fe

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for 4xperss (version 1.0.0).
If you installed it — respond
Remove 4xperss from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If 4xperss 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. 4xperss on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Credits

Amazon Inspector · finder
OpenSSF: Package Analysis · finder

Detect & block this

O3 blocks 4xperss-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database