Which versions of bytepack-probe-a7x3 are malicious?

The following npm versions of bytepack-probe-a7x3 are flagged malicious: 1.0.0, 1.0.1. Treat any of these as compromised.

How do I remediate bytepack-probe-a7x3 if I installed it?

Remove bytepack-probe-a7x3 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 bytepack-probe-a7x3 — how do I know if it already compromised me?

If bytepack-probe-a7x3 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 bytepack-probe-a7x3 part of a known attack campaign?

Yes — bytepack-probe-a7x3 is associated with the IN-MAL-2026-020275, IN-MAL-2026-020276 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 bytepack-probe-a7x3 across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for bytepack-probe-a7x3 (2 malicious versions).

Malicious package

bytepack-probe-a7x3npm

Advisory published Sep 21, 2026Updated Sep 21, 2026

bytepack-probe-a7x3 is a confirmed malicious npm package (MAL-2026-16364) that executes malicious code on install (malicious versions 1.0.0, 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bytepack-probe-a7x3 (npm)

MAL-2026-16364

Immediate action

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

npm uninstall bytepack-probe-a7x3

What this malware does

package.json declares a dependency leak-internal whose source is the HTTPS tarball URL https://src-ssrf.bytedance.net/ssrf/probe.tgz rather than a registry version range. On npm install, npm fetches and installs whatever bytes that URL currently returns, executing any lifecycle scripts contained in the fetched tarball. There is no version pin, no integrity hash, and no signature check, so the code executed on the installer's machine is whatever the operator of that host serves at the moment of install. The hostname suggests an SSRF-probe artifact hosted on an internal-looking domain, and the dependency name leak-internal together with the path segment ssrf/probe.tgz indicates the fetched payload is intended to run probing behavior inside the installer's network.

Malicious versions

2 flagged

1.0.01.0.1

Indicators of compromise (SHA-256)

1f158536e9d84e6cee18e2a3ce84869e34f1564ec18a1313a9e8c03b304e3d70

68a86424e95be011ab100ba078387e7b3ba51169d6027bce287d1f5527a6c437

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for bytepack-probe-a7x3 (2 malicious versions).
If you installed it — respond
Remove bytepack-probe-a7x3 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 bytepack-probe-a7x3 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. bytepack-probe-a7x3 on npm has been identified as a malicious package (versions 1.0.0, 1.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020275IN-MAL-2026-020276

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks bytepack-probe-a7x3-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