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CVE-2026-102937BIT-virtualenv-2026-102937GHSA-x78j-v8h9-3j2qPYSEC-2026-4014

virtualenv: Command injection via --prompt in activate.bat (batch activator)

pypa virtualenvpipLibraries & packages
Open in ThreatlineRecord JSON
CVSS
7.3High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.14%Chance of exploitation activity in the next 30 days, higher than 3% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in21.7.12Fixed versionGitHub
Published29 Sep 2026Updated 6 Oct 2026CVE List

What fixes it

  • 21.7.12virtualenv, pipGitHub
  • 21.7.12virtualenv, PyPIOSVpip install "virtualenv>=21.7.12"

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

BatchActivator.quote() returned its input unchanged, the only activator with no escaping at all. --prompt, the VIRTUALENV_PROMPT environment variable, and the config file all set the prompt, and activate.bat writes it straight into @set "VAR=value". A prompt containing a double quote closes that string early, and whatever follows runs as live cmd.exe syntax:

$ virtualenv --prompt 'x" & calc & "' venv
$ venv\Scripts\activate.bat

runs calc the moment someone activates the environment. Confirmed on a real Windows runner. Anyone who templates a prompt from untrusted input (a CI job using a branch name, a wrapper script deriving an environment name from user input) hands an attacker code execution in the shell of anyone who activates the resulting venv on Windows.

Fixed in 21.7.12 by escaping the characters cmd.exe treats as live syntax inside this construct. Fix: https://github.com/pypa/virtualenv/pull/3250

Text from GitHub Advisory Database

Affected versions 53

  • virtualenv, pip<= 21.7.11GitHub
  • virtualenvaffected: < 21.7.12CVE List
  • virtualenv, PyPIfrom first release, fixed in 21.7.12OSV
  • virtualenv, PyPI0.8OSV
  • virtualenv, PyPI0.8.1OSV
  • virtualenv, PyPI0.8.2OSV
  • virtualenv, PyPI0.8.3OSV
  • virtualenv, PyPI0.8.4OSV
  • virtualenv, PyPI0.9OSV
  • virtualenv, PyPI0.9.1OSV
  • virtualenv, PyPI0.9.2OSV
  • virtualenv, PyPI1.0OSV
  • virtualenv, PyPI1.1OSV
  • virtualenv, PyPI1.10OSV
  • virtualenv, PyPI1.10.1OSV
  • virtualenv, PyPI1.11OSV
  • virtualenv, PyPI1.11.1OSV
  • virtualenv, PyPI1.11.2OSV
  • virtualenv, PyPI1.11.3OSV
  • virtualenv, PyPI1.11.4OSV
  • virtualenv, PyPI1.11.5OSV
  • virtualenv, PyPI1.11.6OSV
  • virtualenv, PyPI1.2OSV
  • virtualenv, PyPI1.3OSV
  • virtualenv, PyPI1.3.1OSV
  • virtualenv, PyPI1.3.2OSV
  • virtualenv, PyPI1.3.3OSV
  • virtualenv, PyPI1.3.4OSV
  • virtualenv, PyPI1.4OSV
  • virtualenv, PyPI1.4.1OSV
  • virtualenv, PyPI1.4.2OSV
  • virtualenv, PyPI1.4.3OSV
  • virtualenv, PyPI1.4.4OSV
  • virtualenv, PyPI1.4.5OSV
  • virtualenv, PyPI1.4.6OSV
  • virtualenv, PyPI1.4.7OSV
  • virtualenv, PyPI1.4.8OSV
  • virtualenv, PyPI1.4.9OSV
  • virtualenv, PyPI1.4rc1OSV
  • virtualenv, PyPI1.5OSV
  • virtualenv, PyPI1.5.1OSV
  • virtualenv, PyPI1.5.2OSV
  • virtualenv, PyPI1.6OSV
  • virtualenv, PyPI1.6.1OSV
  • virtualenv, PyPI1.6.2OSV
  • virtualenv, PyPI1.6.3OSV
  • virtualenv, PyPI1.6.4OSV
  • virtualenv, PyPI1.7OSV
  • virtualenv, PyPI1.7.1OSV
  • virtualenv, PyPI1.7.1.1OSV
  • virtualenv, PyPI1.7.1.2OSV
  • virtualenv, PyPI1.7.2OSV
  • virtualenv, PyPI1.8OSV

References 9