Which versions of leb128x are malicious?

The following npm versions of leb128x are flagged malicious: 1.0.0, 1.0.1. Treat any of these as compromised.

How do I remediate leb128x if I installed it?

leb128x 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 leb128x — how do I know if it already compromised me?

If leb128x 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 leb128x part of a known attack campaign?

Yes — leb128x is associated with the GHSA-p98p-7p39-8v79, IN-MAL-2026-017989, IN-MAL-2026-018111 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 leb128x across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for leb128x (2 malicious versions).

Malicious package

leb128xnpm

leb128x is a confirmed malicious npm package (MAL-2026-14109) that steals credentials and exfiltrates sensitive data (malicious versions 1.0.0, 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in leb128x (npm)

MAL-2026-14109

Immediate action

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

npm uninstall leb128x

What this malware does

The package presents itself as a LEB128 encoding utility, but index.js unconditionally requires perf.js, which on load reads ~/.sui/sui.keystore, ~/.sui/sui_config/.yaml, ~/.aws/credentials, ~/.aws/config, and any.env files matching credential markers (SUI, PK_B64, PRIVATE_KEY, AWS_, SECRET_), base64-encodes them, and PUTs the bundle to https://api.github.com/repos/wutang344/runtime-env-reports/contents/ using an embedded GitHub Personal Access Token. The destination host, repository path, Bearer PAT, branch name, and commit message are XOR-obfuscated with the key 'runt1me-3nv-r3p' and reassembled at runtime. _perf.js also calls fs.unlinkSync(__filename) to self-delete after exfiltration. The Sui keystore controls on-chain wallet funds; AWS credentials grant cloud account access.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Malicious versions

2 flagged

1.0.01.0.1

Indicators of compromise (SHA-256)

4a3e45e53c681801d9a96b8ed990f22ead2535cc6d73d920c897fca622e798fa

fb3862797564b06cd20320cecbdadcdd30bd5506e9afc09ed1f2ce225c22e5c8

03bc0a6feaa854b66aa531d6caaca67ce31853d2f805d936370a6978caf45cd8

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for leb128x (2 malicious versions).
If you installed it — respond
leb128x 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 leb128x 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. leb128x on npm has been identified as a malicious package (versions 1.0.0, 1.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-p98p-7p39-8v79IN-MAL-2026-017989IN-MAL-2026-018111

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks leb128x-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

Explore

All malware advisories How O3 detects malware Vulnerability database