---
id: CVE-2020-15523
title: >-
  In Python 3.6 through 3.6.10, 3.7 through 3.7.8, 3.8 through 3.8.4rc1, and 3.9
  through 3.9.0b4 on Windows, a Trojan horse python3.dll might be used in cases
  where CPython is embedded in a native application
summary: >-
  In Python 3.6 through 3.6.10, 3.7 through 3.7.8, 3.8 through 3.8.4rc1, and 3.9
  through 3.9.0b4 on Windows, a Trojan horse python3.dll might be used in cases
  where CPython is embedded in a native application. This occurs because
  python3X.…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-427
  - CWE-908
vendor: python
product: python
affected:
  - 'python >= 3.5.0, < 3.5.10'
  - 'python >= 3.6.0, < 3.6.12'
  - 'python >= 3.7.0, < 3.7.9'
  - 'python >= 3.8.0, < 3.8.4'
  - python = 3.8.4
  - python = 3.9.0
  - snapcenter
patched:
  - python 3.8.4
published: '2020-07-04'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:24.240'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-15523'
references:
  - url: 'https://bugs.python.org/issue29778'
    label: cve@mitre.org
  - url: 'https://github.com/python/cpython/pull/21297'
    label: cve@mitre.org
  - url: 'https://security.netapp.com/advisory/ntap-20210312-0004/'
    label: cve@mitre.org
  - url: 'https://bugs.python.org/issue29778'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/python/cpython/pull/21297'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20210312-0004/'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00919
epssPercentile: 0.5902
ingestedAt: '2026-10-08T22:11:53.718Z'
---

## Overview

In Python 3.6 through 3.6.10, 3.7 through 3.7.8, 3.8 through 3.8.4rc1, and 3.9 through 3.9.0b4 on Windows, a Trojan horse python3.dll might be used in cases where CPython is embedded in a native application. This occurs because python3X.dll may use an invalid search path for python3.dll loading (after Py_SetPath has been used). NOTE: this issue CANNOT occur when using python.exe from a standard (non-embedded) Python installation on Windows.

## Affected

- `python >= 3.5.0, < 3.5.10`
- `python >= 3.6.0, < 3.6.12`
- `python >= 3.7.0, < 3.7.9`
- `python >= 3.8.0, < 3.8.4`
- `python = 3.8.4`
- `python = 3.9.0`
- `snapcenter`

## Remediation

Upgrade past the affected range:

- `python 3.8.4`