Which versions of runtimekit are malicious?

The following npm versions of runtimekit are flagged malicious: 1.0.1, 1.0.5. Treat any of these as compromised.

How do I remediate runtimekit if I installed it?

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

If runtimekit 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 runtimekit part of a known attack campaign?

Yes — runtimekit is associated with the IN-MAL-2026-007537, IN-MAL-2026-007538 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 runtimekit 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 runtimekit (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging runtimekit across your stack and pipelines.

Malicious package

runtimekitnpm

runtimekit is a confirmed malicious npm package (MAL-2026-6477) that executes malicious code on install (malicious versions 1.0.1, 1.0.5). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in runtimekit (npm)

MAL-2026-6477

Immediate action

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

npm uninstall runtimekit

What this malware does

lib/index.cjs and lib/index.mjs (re-required from lib/readonly.cjs) contain a self-executing IIFE that decodes two opaque strings via a custom shuffle routine (YWG), recovers the identifier constructor from one of them, retrieves the Function constructor via property access, then builds and invokes nested Function-constructor calls — Function('', Function('', decoded1))(decoded2)(7942) — executing arbitrary decoded JavaScript at module load. Before the synthesis, the loader assigns global.r = require and global.m = module, deliberately smuggling Node's require and module bindings into the global scope so the dynamically constructed function (which does not inherit the module's closure) can reach them. A marker global._V = "A6-Shadow-16" is also set. The package advertises itself as a validation/runtime utility but ships an obfuscated self-injecting loader with no legitimate purpose for hiding code from Function constructors. Any consumer that does require('runtimekit') or require('runtimekit/readonly') runs the decoded payload in-process with full Node privileges.

Malicious versions

2 flagged

1.0.11.0.5

Indicators of compromise (SHA-256)

d52981221e2907355a06d5d2ba981b377ba2aa468401bbaadb3621fab01ac0de

ffa393dec171ebd22b63776d7550006d3f9f60ad8726ce1153784080e9038acd

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 runtimekit (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging runtimekit across your stack and pipelines.
If you installed it — respond
Remove runtimekit 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 runtimekit 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 runtimekit 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. runtimekit on npm has been identified as a malicious package (versions 1.0.1, 1.0.5 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-007537IN-MAL-2026-007538

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks runtimekit-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

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