Which versions of pkg-fallback are malicious?

The following npm versions of pkg-fallback are flagged malicious: 1.1.0. Treat any of these as compromised.

How do I remediate pkg-fallback if I installed it?

Remove pkg-fallback 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 pkg-fallback — how do I know if it already compromised me?

If pkg-fallback 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 pkg-fallback part of a known attack campaign?

Yes — pkg-fallback is associated with the IN-MAL-2026-007723 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 pkg-fallback 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 pkg-fallback (version 1.1.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging pkg-fallback across your stack and pipelines.

Malicious package

pkg-fallbacknpm

pkg-fallback is a confirmed malicious npm package (MAL-2026-6570) that executes malicious code on install (malicious version 1.1.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in pkg-fallback (npm)

MAL-2026-6570

Immediate action

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

npm uninstall pkg-fallback

What this malware does

Package advertises itself as a small string-manipulation library (trim, case, pad, wrap) but its install-time behavior is a dropper. package.json declares a direct dependency native-bridge as http://157.254.194.200:8080/native-bridge-1.0.0.tar.gz — a plain-HTTP tarball on a bare IP unrelated to any publisher. On npm install, npm fetches that arbitrary tarball and installs it into the consumer's node_modules tree, running its own lifecycle scripts. Additionally, the declared postinstall script (scripts/check-binary.js) downloads a second tarball, npm-dependency-payload-1.0.0.tar.gz, over plain HTTP from the same bare IP and writes it to .cache/native.tgz with errors silently swallowed. Neither fetch is pinned, hash-verified, or sourced from publisher infrastructure, and the shipped tarball contains no native source code that would justify a native-bridge dependency. The string-utility cover story is inconsistent with the install-time behavior, which is the deliberate-evasion shape of a supply-chain dropper.

Malicious versions

1 flagged

1.1.0

Indicators of compromise (SHA-256)

c97ea590e70f499f40938e093cd6a09a13b95030872968b5d325fee8a595f31c

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for pkg-fallback (version 1.1.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging pkg-fallback across your stack and pipelines.
If you installed it — respond
Remove pkg-fallback 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 pkg-fallback 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 pkg-fallback 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. pkg-fallback on npm has been identified as a malicious package (version 1.1.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-007723

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks pkg-fallback-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