uvhttp-customPyPI
Advisory published Updated
uvhttp-custom is a confirmed malicious PyPI package (MAL-2026-15863) that steals credentials and exfiltrates sensitive data (malicious versions 1.7.9, 1.8.1, 1.9.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in uvhttp-custom (PyPI)
What this malware does
setup.py contains an obfuscated payload of the form (lambda __: exec(__import__('base64').b64decode('...').decode()))(None) alongside an otherwise-benign setuptools import. The decoded payload writes a bundled script.ps1 to disk and invokes powershell -ExecutionPolicy Bypass -File script.ps1. The PowerShell script uses System.Net.WebClient.DownloadFile to fetch a Windows executable from cdn.discordapp.com/attachments/1532996358427115552/1539384056284717066/enlisted_launcher_1.0.3.190-movn8hpfe.exe into %TEMP%\file.exe and launches it via Start-Process with -WindowStyle Hidden. No hash or signature verification is performed. The payload also invokes os.system("calc"). Running pip install uvhttp-custom on Windows therefore causes the installer's machine to download and silently execute an opaque, unsigned binary from an anonymous Discord CDN URL.
During installation, obfuscated code downloads and executes an executable. It appears to be a game launcher.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-09-uvhttp-custom
Reasons (based on the campaign):
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The package overrides the install command in setup.py to execute malicious code during installation.
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Downloads and executes a remote executable.
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obfuscation
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for uvhttp-custom (3 malicious versions).
If you installed it — respond
uvhttp-custom 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 uvhttp-custom 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
Campaign
References
Credits
- Amazon Inspector · finder
- Kamil Mańkowski (kam193) · reporter
Detect & block this
O3 blocks uvhttp-custom-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.