---
id: MAL-2026-16128
title: Malicious code in pymem-win (PyPI)
summary: Malicious code in pymem-win (PyPI)
severity: critical
exploited: true
vendor: pymem-win
product: pymem-win
ecosystem: pip
affected:
  - pymem-win
published: '2026-09-11'
updated: '2026-09-11'
sourceUpdated: '2026-09-11T23:30:06.364603204Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/MAL-2026-16128'
references:
  - url: 'https://bad-packages.kam193.eu/pypi/package/pymem-win'
  - url: 'https://pypi.org/project/Pymem-win/1.14.6/'
tags:
  - osv
  - pip
  - malware
ingestedAt: '2026-09-12T03:13:01.742Z'
---

## Overview


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

## Source: amazon-inspector (4c611131ac135f4608698ce56eebd7dc89623b591510a050f2059369c9d51bbf)
Pymem-win is a near-verbatim copy of the legitimate upstream Pymem package (reusing its description, repository URL github.com/srounet/Pymem, and author identity Fabien Reboia <srounet@gmail.com>) republished under a confusable name. The top-level pymem/__init__.py contains a one-line loader that reverses a bytes literal, base64-decodes it, zlib-decompresses it, and passes the result to exec(). This runs unconditionally on `import pymem`, handing full in-process code execution to a payload deliberately hidden behind three stacked transforms. The multi-layer obfuscation around an exec target has no legitimate purpose in a library import path; combined with the typosquat cover story that reuses the upstream author's identity, the package's function on install/import is to run attacker-chosen code inside any process that imports it.

## Source: kam193 (82eb1f11c9b56a2f2c3e97530db43ef94784a2c75697223828403927b0528477)
During import, the obfuscated code downloads and executes an executable. The remote executable did not exist during analysis, but the repository used to host it overlaps with previous campaign 2026-07-yt-api-dlp


---

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


Campaign: 2026-09-pymem-win


Reasons (based on the campaign):


 - obfuscation


 - Downloads and executes a remote executable.


 - clones-real-package


## Affected packages

- `pymem-win`

## Remediation

Refer to the advisory for the patched release.