# MAL-2026-15863: Malicious code in uvhttp-custom (PyPI)


- **Type:** Malicious package
- **Package:** `uvhttp-custom` (PyPI)
- **Published:** 3 Sep 2026

## What is MAL-2026-15863?

MAL-2026-15863 is a malicious package in uvhttp-custom, published on 3 Sep 2026. 

### Official description

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):

 - The package overrides the install command in setup.py to execute malicious code during installation.

 - Downloads and executes a remote executable.

 - obfuscation

## What should I do about MAL-2026-15863?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-15863 is a malicious package: uvhttp-custom (PyPI). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-15863/ (Markdown: https://insights.sbomify.com/MAL-2026-15863/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-15863

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-15863/
Summaries are generated and may contain mistakes; the official description above is the record.