Which versions of let1x5 are malicious?

The following npm versions of let1x5 are flagged malicious: 8.0.0. Treat any of these as compromised.

How do I remediate let1x5 if I installed it?

Remove let1x5 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 let1x5 — how do I know if it already compromised me?

If let1x5 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 let1x5 part of a known attack campaign?

Yes — let1x5 is associated with the RLMA-2026-01399 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 let1x5 across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for let1x5 (version 8.0.0).

Malicious package

let1x5npm

Advisory published Mar 18, 2026Updated Mar 23, 2026

let1x5 is a confirmed malicious npm package (MAL-2026-1769) that executes malicious code on install (malicious version 8.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in let1x5 (npm)

MAL-2026-1769

Immediate action

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

npm uninstall let1x5

What this malware does

The package let1x5 was found to contain malicious code.

Malicious versions

1 flagged

8.0.0

Indicators of compromise (SHA-256)

1f197a6a4d639ecbe0bcc857a6b2adcc4127de87375f66aee9f7dc74e0ac7b22

60350402f71e67787e3621f0ff0d1eae05e0b3b386905fa9f0584fe63fa772d7

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for let1x5 (version 8.0.0).
If you installed it — respond
Remove let1x5 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 let1x5 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. let1x5 on npm has been identified as a malicious package (version 8.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-01399

Credits

Amazon Inspector · finder
ReversingLabs · finder

Detect & block this

O3 blocks let1x5-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