---
id: "MAL-2026-14545"
kind: "package"
aliases: ["MAL-2026-14545"]
title: "Malicious code in pybitjs (PyPI)"
severity: "critical"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "pybitjs", "fixed": [], "affected": "= 0.1.0", "ecosystem": "pypi"}]
ecosystems: ["pypi"]
tags: ["malicious", "package"]
not_affected_if: []
published_at: "2026-08-26T19:21:41+00:00"
first_seen_at: "2026-10-26T20:51:57+00:00"
updated_at: "2026-10-26T21:12:36+00:00"
sources: [{"source": "osv-malicious", "url": "https://osv.dev/vulnerability/MAL-2026-14545", "first_seen_at": "2026-10-26T20:51:57+00:00"}]
---

# Malicious code in pybitjs (PyPI)

## Affected

- pypi:pybitjs affected = 0.1.0 fixed ?

## Timeline

- 2026-10-26T20:51:57+00:00 osv-malicious https://osv.dev/vulnerability/MAL-2026-14545

## From the sources

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

## Source: amazon-inspector (611713d33cb9efee440b0a416812cbb2ceda3d43c0cdc73c1f8b353400209df5)
The package's setuptools cmdclasses (BuildPy, Develop) invoke `node pybitjs/js/main.js` during `pip install`, and write a `pybitjs.pth` file containing `import pybitjs._autorun; pybitjs._autorun.run_main_js_once()` so the same Node.js payload is re-executed on every subsequent Python interpreter startup. The bundled `pybitjs/js/main.js` is heavily string-array obfuscated (obfuscator.io style `_0x240a` / `_0x4963`) and implements an EtherHiding-style C2: it queries Ethereum JSON-RPC endpoints (drpc.org, publicnode.com, blockscout, etherscan-like API) for transactions involving the hardcoded address `0xa322E5f3...`, extracts an IPv4 from the transaction data, HTTP-fetches an XOR-encrypted blob from that IP, decrypts it, and passes the decrypted content to `eval(...)` and to `spawn('node', ['-e', <payload>], {detached:true}).unref()`. Because the C2 host is dereferenced from an on-chain transaction, the destination is attacker-mutable, and installing or launching Python with this package present causes arbitrary attacker-controlled code to be fetched and executed on the installer's host.

## Source: kam193 (8cf3b72788a1ad482702768ea3b7f958793a0997cf77342578c31bc6dcfd23c8)
Package embeds obfuscated, JS-based malware downloading further remote stages. The code is triggered during building the package and on every Python startup (via PTH file). The next-stage IP is delivered via a blockchain. 

The payload and embedded IoCs are consistent with campaigns attributed to Lazarus APT/PolinRider.


---

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


Campaign: 2026-08-pybitjs


Reasons (based on the campaign):


 - obfuscation


 - Downloads and executes a remote malicious script.


 - malware


 - abuses-pth


 - 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_