Which versions of mcc-data are malicious?

The following npm versions of mcc-data are flagged malicious: 4.99.99. Treat any of these as compromised.

How do I remediate mcc-data if I installed it?

Remove mcc-data 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 mcc-data — how do I know if it already compromised me?

If mcc-data 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 mcc-data part of a known attack campaign?

Yes — mcc-data is associated with the RLMA-2026-01784 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 mcc-data across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for mcc-data (version 4.99.99).

Malicious package

mcc-datanpm

Advisory published Mar 24, 2026Updated Apr 7, 2026

mcc-data is a confirmed malicious npm package (MAL-2026-2370) that executes malicious code on install (malicious version 4.99.99). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in mcc-data (npm)

MAL-2026-2370

Immediate action

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

npm uninstall mcc-data

What this malware does

The package mcc-data was found to contain malicious code.

Malicious versions

1 flagged

4.99.99

Indicators of compromise (SHA-256)

e46f732462a71303155d1d444fa4d1743a9a1445198baf24f5a0ba363cdb881e

fdebe75a625bd46c208016a8524101fa4abd3e66215fcc1bb509a7c235be3be8

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for mcc-data (version 4.99.99).
If you installed it — respond
Remove mcc-data 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 mcc-data 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. mcc-data on npm has been identified as a malicious package (version 4.99.99 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-01784

Credits

Amazon Inspector · finder
ReversingLabs · finder

Detect & block this

O3 blocks mcc-data-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