GHSA-x78j-v8h9-3j2q
virtualenv: Command injection via --prompt in activate.bat (batch activator)
At a glance
- Published
- Updated
- CVE
- CVE-2026-102937
- Aliases
- BIT-virtualenv-2026-102937, PYSEC-2026-4014
- CVSS_V4
- CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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: ```console $ 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
Affected packages
| Package | Versions |
|---|---|
| PyPI · virtualenv | introduced 0, fixed 21.7.12 |
References
- https://github.com/pypa/virtualenv/security/advisories/GHSA-x78j-v8h9-3j2q WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-102937 ADVISORY
- https://github.com/pypa/virtualenv/pull/3250 WEB
- https://github.com/pypa/virtualenv/commit/d721ff140ce4afdc2a9b76751e4584e25d9fbea6 WEB
- https://github.com/pypa/advisory-database/tree/main/vulns/virtualenv/PYSEC-2026-4014.yaml WEB
- https://github.com/pypa/virtualenv PACKAGE
- https://github.com/pypa/virtualenv/releases/tag/21.7.12 WEB
- https://pypi.org/project/virtualenv WEB
Sources
| Source | Licence |
|---|---|
| OSV.dev | CC-BY 4.0 — GitHub Advisory Database |