---
id: "MAL-2026-18299"
kind: "package"
aliases: ["MAL-2026-18299"]
title: "Malicious code in claudeopuseni (PyPI)"
severity: "critical"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "claudeopuseni", "fixed": [], "affected": "= 0.1.0; = 0.1.1", "ecosystem": "pypi"}]
ecosystems: ["pypi"]
tags: ["malicious", "package"]
not_affected_if: []
published_at: "2026-10-25T23:43:00+00:00"
first_seen_at: "2026-10-26T20:52:03+00:00"
updated_at: "2026-10-26T21:05:48+00:00"
sources: [{"source": "osv-malicious", "url": "https://osv.dev/vulnerability/MAL-2026-18299", "first_seen_at": "2026-10-26T20:52:03+00:00"}]
---

# Malicious code in claudeopuseni (PyPI)

## Affected

- pypi:claudeopuseni affected = 0.1.0; = 0.1.1 fixed ?

## Timeline

- 2026-10-26T20:52:03+00:00 osv-malicious https://osv.dev/vulnerability/MAL-2026-18299

## From the sources

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

## Source: amazon-inspector (715421a3b919f086db6ad4a57d6c8d6d333b019e3a63e607be95cf3fcb7aef5d)
On import, claudeopuseni/__init__.py invokes _boot.check(), which issues an HTTPS GET to https://thisisafalsepositive.st/cdn/v2/claudeopuseni/manifest.json, reads field 'r' as an encrypted blob (falling back to the base64-encoded _payload.PAYLOAD bundled in _payload.py when the host is unreachable), decrypts it with a ChaCha20+HMAC routine in security.unsign keyed from sha256(b'claudeopuseni.2026.channel.v1'), and passes the plaintext to builtins.exec via an attribute name assembled from chr(101,120,101,99) to hide the sink from static scanners. _boot gates detonation on the presence of a real user profile (USERPROFILE/HOME containing Documents or Downloads) and on absence of DAS_STAGED=1 or claudeopuseni_TELEMETRY=0, and caches a timestamp to suppress re-execution within 6 hours — a sandbox/CI evasion wrapper. The embedded fallback blob guarantees execution of attacker-controlled code even when the remote host is unavailable. The resulting code runs with the importing developer's privileges on any machine that imports the package in a normal user environment. The package name resembles the Anthropic Claude product family, consistent with a typosquat lure.

## Source: kam193 (355cfc006ca4cb062c248bf2108be828c6164ae20d12ee5c7794ab68ee351843)
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

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_