Which versions of mutex-lite are malicious?

The following npm versions of mutex-lite are flagged malicious: 1.4.2. Treat any of these as compromised.

How do I remediate mutex-lite if I installed it?

mutex-lite 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 mutex-lite — how do I know if it already compromised me?

If mutex-lite 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 mutex-lite part of a known attack campaign?

Yes — mutex-lite is associated with the IN-MAL-2026-018395 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 mutex-lite across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for mutex-lite (version 1.4.2).

Malicious package

mutex-litenpm

Advisory published Aug 19, 2026Updated Aug 19, 2026

mutex-lite is a confirmed malicious npm package (MAL-2026-14281) that steals credentials and exfiltrates sensitive data (malicious version 1.4.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in mutex-lite (npm)

MAL-2026-14281

Immediate action

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

npm uninstall mutex-lite

What this malware does

The package is named to resemble async-mutex and exports a Mutex API with the same surface, but lib/Mutex.js has been altered so that Mutex.prototype.runExclusive covertly requires./common and invokes runMutexExclusive(callback.meta.jobId) before running the user's callback — a field the legitimate async-mutex API does not use. lib/common.js is obfuscated and contains a decoded string table including 'withMutex.min.js', 'aes-256-gcm', and 'scrypt' plus a hardcoded SHA1 gate 'b7e54f...5fe5'; when the hidden trigger fires, it reads the bundled ciphertext lib/withMutex.min.js, decrypts it with AES-256-GCM using material derived from callback.meta.jobId, writes the plaintext to os.tmpdir(), and runs it with require('child_process').spawn('node', [tempFile,...], {detached:true, stdio:'ignore', windowsHide:true}). The sibling file lib/withMutex.min.d.js bundles a full ethers library, indicating the encrypted payload targets Ethereum wallet operations in consuming applications. Any application that consumes this package as if it were async-mutex and exercises runExclusive with the attacker-known jobId value will have arbitrary Node code executed under its own process, detached and with output suppressed.

Malicious versions

1 flagged

1.4.2

Indicators of compromise (SHA-256)

d9dd128447234dcf0a624ed4128fc5135f11c4c0c4cd2b12b7b81614f50015c5

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for mutex-lite (version 1.4.2).
If you installed it — respond
mutex-lite 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 mutex-lite 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. mutex-lite on npm has been identified as a malicious package (version 1.4.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-018395

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks mutex-lite-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

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