---
id: "MAL-2026-16128"
kind: "package"
aliases: ["MAL-2026-16128"]
title: "Malicious code in pymem-win (PyPI)"
severity: "critical"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "pymem-win", "fixed": [], "affected": "= 1.14.0; = 1.14.1; = 1.14.4; = 1.14.5; = 1.14.6", "ecosystem": "pypi"}]
ecosystems: ["pypi"]
tags: ["malicious", "package"]
not_affected_if: []
published_at: "2026-09-11T14:47:19+00:00"
first_seen_at: "2026-10-26T20:51:57+00:00"
updated_at: "2026-10-26T21:10:31+00:00"
sources: [{"source": "osv-malicious", "url": "https://osv.dev/vulnerability/MAL-2026-16128", "first_seen_at": "2026-10-26T20:51:57+00:00"}]
---

# Malicious code in pymem-win (PyPI)

## Affected

- pypi:pymem-win affected = 1.14.0; = 1.14.1; = 1.14.4; = 1.14.5; = 1.14.6 fixed ?

## Timeline

- 2026-10-26T20:51:57+00:00 osv-malicious https://osv.dev/vulnerability/MAL-2026-16128

## From the sources

---
_-= 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

---

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