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 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 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?

Search your lockfiles and build artifacts for json-bigint-rs (version 0.1.1).

Malicious package

json-bigint-rsnpm

Advisory published Sep 30, 2026Updated Sep 30, 2026

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
Search your lockfiles and build artifacts for json-bigint-rs (version 0.1.1).
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 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. 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

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