Which versions of json-bigint-rs are malicious?

The following npm versions of json-bigint-rs are flagged malicious: 0.1.1. Treat any of these as compromised.

How do I remediate json-bigint-rs if I installed it?

Remove json-bigint-rs 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 json-bigint-rs — how do I know if it already compromised me?

If json-bigint-rs 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 json-bigint-rs part of a known attack campaign?

Yes — json-bigint-rs is associated with the IN-MAL-2026-020793 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 json-bigint-rs 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 json-bigint-rs (version 0.1.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging json-bigint-rs across your stack and pipelines.

Malicious package

json-bigint-rsnpm

json-bigint-rs is a confirmed malicious npm package (MAL-2026-17312) that executes malicious code on install (malicious version 0.1.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in json-bigint-rs (npm)

MAL-2026-17312

Immediate action

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

npm uninstall json-bigint-rs

What this malware does

On require(), index.js instantiates the shipped json-bigint-rs.wasm module and, for imports declared under the 'wasm:js/string-constants' module namespace, exposes each descriptor's name as an externref global. This mechanism smuggles a full JavaScript payload as WASM import-descriptor names, hiding it from JS-only source scanners. The reconstructed payload is an IIFE wired to node:vm.runInThisContext / runInNewContext that polls three hardcoded hosts (rs.undotest.top, rs.lightnight.top, rs.belivelight.top) every 30 seconds and executes the response body as JavaScript in-process with access to console and process. Execution is gated by NODE_ENV==='production', so the dropper stays dormant on developer machines and activates on servers and CI. The remote hosts are mutable and unrelated to any documented publisher; the behavior is undocumented in README. The package name and stated purpose (a bignum JSON parser) provide cover for a delivery vehicle whose only observable install/require-time effect is fetching and evaluating attacker-chosen JavaScript.

Malicious versions

1 flagged

0.1.1

Indicators of compromise (SHA-256)

7f5b71b917a0504deb87a597d9d07527179c2d6bb9ec1f836caa34d6145aa043

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 json-bigint-rs (version 0.1.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging json-bigint-rs across your stack and pipelines.
If you installed it — respond
Remove json-bigint-rs 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 json-bigint-rs 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 json-bigint-rs 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. json-bigint-rs on npm has been identified as a malicious package (version 0.1.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020793

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks json-bigint-rs-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