Which versions of ensmallen are malicious?

The following PyPI versions of ensmallen are flagged malicious: 0.8.101. Treat any of these as compromised.

How do I remediate ensmallen if I installed it?

Remove ensmallen 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 network activity or persistence. Use O3 Security's dependency scanner to confirm the package and its artifacts are fully purged across your stack.

Is ensmallen part of a known attack campaign?

Yes — ensmallen is associated with the 2026-06-compr-woodpecker campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

Can O3 Security detect ensmallen in my codebase?

Yes. O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, blocking ensmallen and packages like it before any post-install script runs.

Malicious package

ensmallenPyPI

Malicious code in ensmallen (PyPI) Remove it immediately and rotate any exposed credentials.

MAL-2026-5315

Immediate action

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

pip uninstall ensmallen

What this malware does

Versions 0.8.101 were compromised.

Compromised packages start an obfuscated infostealer. The infostealer is a heavily obfuscated JavaScript code executed using Bun runtime on Python startup. It collectes all kinds of sensitive data, including API keys, credentials to package repositories, cryptocurrency assets, password manager data. Infostealer actively queries online services to collect additional secrets as well as attempts to gain persistence and spread further by publishing infected packages using collected credentials. Data are exfiltrated likely using Github. The code seems to threaten to wipe the user's data if it detects invalid GitHub tokens. Cleanup should be done with caution.

It seems to be related to the recent Mini Shai Hulud campaign.

Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2026-06-compr-woodpecker

Reasons (based on the campaign):

compromised-package
exfiltration-env-variables
exfiltration-cloud-tokens
exfiltration-credentials
abuses-pth
obfuscation
infostealer
The package contains code to detect if it is running in a sandbox environment.
exfiltration-crypto
files-exfiltration
destructive-actions

Malicious versions

1 flagged

0.8.101

Indicators of compromise (SHA-256)

f844af5d6142ffdd36c3697ff26feabb3d79b6f75e5ac403d2ade6460023e04c

3c6c422edc088f6a32a62b1b00176ff3533cba5ed0348b5995a9ed00dc5d3e65

dad59933069ee649fd7762c6e22fd60e60a2edde36641aede10db352c9ba5980

Frequently asked questions

No. ensmallen on PyPI has been identified as a malicious package (version 0.8.101 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2026-06-compr-woodpecker

References

Credits

Kamil Mańkowski (kam193) · analyst

Scan your dependencies

O3 Security blocks malicious packages like this at install time and in CI.

Supply-chain protection