---
id: MAL-2026-18298
title: Malicious code in claudeopusfile (PyPI)
summary: Malicious code in claudeopusfile (PyPI)
severity: critical
exploited: true
vendor: claudeopusfile
product: claudeopusfile
ecosystem: pip
affected:
  - claudeopusfile
published: '2026-10-25'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T06:45:15.843384220Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/MAL-2026-18298'
references:
  - url: >-
      https://www.virustotal.com/gui/file/d03c42c275f0dbc617428441508c49ae1adcbbc95af4eeb094bca4e4f8943f3e/detection
  - url: 'https://polygonscan.com/address/0x9c0a507300fd902787bb193d80fca5ce6e1bff9a'
  - url: 'https://bad-packages.kam193.eu/pypi/package/claudeopusfile'
  - url: 'https://pypi.org/project/claudeopusfile/0.1.2/'
  - url: 'https://pypi.org/project/claudeopusfile/0.1.1/'
tags:
  - osv
  - pip
  - malware
ingestedAt: '2026-10-26T12:01:30.294Z'
---

## Overview


---
_-= Per source details. Do not edit below this line.=-_

## Source: amazon-inspector (de2f0d45d8a2c0489d082d86a91c63fc5cad53f891b3dd1e976cd7479344c65f)
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.

## Source: kam193 (9a776d104d66cbeec1283bd7a7e9decc15da19a1946dd27c7d7ca632a6cdc2f2)
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


## Affected packages

- `claudeopusfile`

## Remediation

Refer to the advisory for the patched release.