Which versions of buffer-util-internal are malicious?

The following npm versions of buffer-util-internal are flagged malicious: 1.0.13, 1.0.14. Treat any of these as compromised.

How do I remediate buffer-util-internal if I installed it?

buffer-util-internal is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

I already installed buffer-util-internal — how do I know if it already compromised me?

If buffer-util-internal 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 buffer-util-internal part of a known attack campaign?

Yes — buffer-util-internal is associated with the IN-MAL-2026-009668, IN-MAL-2026-009667 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 buffer-util-internal 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 buffer-util-internal (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging buffer-util-internal across your stack and pipelines.

Malicious package

buffer-util-internalnpm

Malicious code in buffer-util-internal (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-10151

Immediate action

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

npm uninstall buffer-util-internal

What this malware does

Package impersonates Feross Aboukhadijeh's widely-used buffer package, copying its author, repository, contributors, and description metadata while publishing under the name buffer-util-internal. The main module index.js contains a top-level IIFE that base64-decodes a hardcoded URL (decoding to https://www.jsonkeeper.com/b/PT0ON), fetches a JSON document from that anonymous paste host, and passes the response's content field directly to eval. The destination URL is hidden behind a variable named tokenStringRe with a misleading // Random string to generate strong random value comment, alongside a second base64 string referencing a sibling paste id. Because the fetched content is attacker-mutable, every consumer that requires this package executes whatever JavaScript the paste host serves at that moment — a full remote code execution primitive on the installer at require time. The package also declares unusual dependencies (axios, execp, request) inconsistent with the legitimate buffer package.

Malicious versions

2 flagged

1.0.131.0.14

Indicators of compromise (SHA-256)

d329e426a3af00dc4cb53c8535a3e53848f09a1b80e561f84f29c77bffe746d7

f3a255421103fb27bb0157b46a493187a59fab17fc5b9e6f91bc84359b4225d2

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for buffer-util-internal (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging buffer-util-internal across your stack and pipelines.
If you installed it — respond
buffer-util-internal is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If buffer-util-internal 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 buffer-util-internal 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. buffer-util-internal on npm has been identified as a malicious package (versions 1.0.13, 1.0.14 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-009668IN-MAL-2026-009667

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks buffer-util-internal-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring