# MAL-2026-18298: Malicious code in claudeopusfile (PyPI)


- **Type:** Malicious package
- **Package:** `claudeopusfile` (PyPI)
- **Published:** 25 Oct 2026

## What is MAL-2026-18298?

MAL-2026-18298 is a malicious package in claudeopusfile, published on 25 Oct 2026. 

### Official description

setup.py imports claudeopusfile.compat._ensure_compat during pip install. compat.py constructs the string 'exec' from a chr-code tuple (chr(101),chr(120),chr(101),chr(99)) and invokes it via getattr(builtins, _RUN)(compile(code, '<claudeopusfile-compat>', 'exec'),...) on content produced by zlib.decompress(base64.b85decode(_shimdata.DATA)) — an opaque base85+zlib blob shipped in claudeopusfile/_shimdata.py. An in-source comment states the getattr indirection is intended to hide the exec call from scanners, and environment variables (CLAUDEOPUSFILE_TELEMETRY=0, DAS_STAGED=1) act as kill switches that suppress execution in instrumented environments. The package additionally ships claudeopusfile/_payload.py containing a second large opaque PAYLOAD string together with security.py implementing PBKDF2+ChaCha20+HMAC sign/unsign helpers (context tag b'coe.'), providing a signed-channel decryption path for a staged second payload. Decoded content runs with the installer's privileges on `pip install`. The package's advertised purpose (prompt-generator utility) has no need to decode and execute an opaque blob at install time.

During installation, obfuscated code is used to fetch code hidden in an image containing a Python application with a native extension module. This module holds an obfuscated infostealer which collects sensitive data and exfiltrates them to a C2 server retrieved from transaction history in the Polygon blockchain.

---

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

Campaign: 2026-09-donutautosellsrc

Reasons (based on the campaign):

 - infostealer

 - Downloads and executes a remote executable.

 - obfuscation

 - The package contains code to detect if it is running in a sandbox environment.

 - malware

 - native-extension

 - steganography

 - c2-in-blockchain

## What should I do about MAL-2026-18298?

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-2026-18298 is a malicious package: claudeopusfile (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-2026-18298/ (Markdown: https://insights.sbomify.com/MAL-2026-18298/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-18298

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-18298/
Summaries are generated and may contain mistakes; the official description above is the record.