---
id: CVE-2026-102938
title: virtualenv is a tool for creating isolated virtual python environments
summary: >-
  virtualenv is a tool for creating isolated virtual python environments. Prior
  to 21.7.11, PyEnvCfg.write() writes prompt values verbatim to the
  line-oriented pyvenv.cfg format while PyEnvCfg._read_values() parses the file
  with str.splitl…
severity: medium
cvss: 5.8
cvssVector: 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N'
cwe:
  - CWE-93
vendor: pypa
product: virtualenv
affected:
  - virtualenv < 21.7.11
published: '2026-09-29'
updated: '2026-09-29'
sourceUpdated: '2026-09-29T21:17:19.047'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102938'
references:
  - url: >-
      https://github.com/pypa/virtualenv/commit/a30f995461043acb6cacbf3a890951563ccf7140
    label: security-advisories@github.com
  - url: 'https://github.com/pypa/virtualenv/pull/3247'
    label: security-advisories@github.com
  - url: 'https://github.com/pypa/virtualenv/releases/tag/21.7.11'
    label: security-advisories@github.com
  - url: 'https://github.com/pypa/virtualenv/security/advisories/GHSA-9h9j-4vrj-gf7g'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
cvssSource: cna
ingestedAt: '2026-09-29T21:49:08.217Z'
---

## Overview

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.11, PyEnvCfg.write() writes prompt values verbatim to the line-oriented pyvenv.cfg format while PyEnvCfg._read_values() parses the file with str.splitlines() and accepts the last value for duplicate keys. An attacker who influences --prompt, VIRTUALENV_PROMPT, or configuration input can insert a recognized line boundary and additional keys, including home, causing consumers to use an attacker-selected base interpreter or corrupted environment metadata. The security impact requires prompt input from outside the operator's trust boundary; directly supplied prompt content primarily corrupts the operator's own environment. This issue is fixed in version 21.7.11.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.