Which versions of exprrrress are malicious?

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

How do I remediate exprrrress if I installed it?

Remove exprrrress 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 exprrrress — how do I know if it already compromised me?

If exprrrress 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 exprrrress across my projects, lockfiles, and CI pipelines?

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

Malicious package

exprrrressnpm

Advisory published Apr 2, 2026Updated Apr 7, 2026

exprrrress is a confirmed malicious npm package (MAL-2026-2443) 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 exprrrress (npm)

MAL-2026-2443

Immediate action

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

npm uninstall exprrrress

What this malware does

The package exprrrress was found to contain malicious code.

The OpenSSF Package Analysis project identified 'exprrrress' @ 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)

387d72a157f82d564aa36555abaa204465c769f4e5a5617458dc6bbc20f12b9a

f3605883655f4870250aaab1c630151c6264e54521d1a711a088871de1fe5ea5

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for exprrrress (version 1.0.0).
If you installed it — respond
Remove exprrrress 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 exprrrress 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. exprrrress 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 exprrrress-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